2006 Ford Mustang - Ruins Alternators & Batteries

25

Asked by Sep 03, 2014 at 08:03 PM about the 2006 Ford Mustang V6 Base

Question type: Maintenance & Repair

Okay, I have owned my 2006 Mustang since September of 2005. It was my first car, I still
own it, and it is an every day driver. It has always been outside - never garage kept (I've
lived in places where there was either no room in garage due to other cars or places
without garages).

In 2010, a light came on that said "Check Charging System" - had the battery & alternator
checked out, everything was good - so I was told. A few months later the car completely
dies on me. Jumping it wouldn't even work. Had the battery replaced to get it from where
I was to a shop - was told that the alternator was bad - had it replaced. That lasted for a
good while - until the same thing happened again during the Fall in 2012 - it died while it
was running and in motion. Once again, the 'Stang left me stranded. Took it to a different
shop this time, thinking I just got a bad alternator from the last shop. Replaced battery &
alternator, once again. Just a little over a year later, in February of this year (2014) - on
my birthday of all days - she does it again! Had a diagnostics test ran on it at the Ford
Dealership in town - they were saying everything was good. Took it back to the same
shop this time - they had a warranty on their parts. They replaced the alternator & battery
for free, since the previous one went out. Here I am.. right at 6 months later - and that
darn Ford is at it again! Over 3 weeks ago, the same thing happened. Took it back to the
same shop - since the alternator from February was still under a new warranty - they
tested the alternator & said it was good, but I had a bad battery. They replaced the
battery, and I got the car back last Thursday morning. Had to run a few errands around
town, but the first time it was in idle, the "Check Charging System" light came back on. I
was hoping they just forgot to reset it - NOPE! Not that particular trip, but my following car
ride, she gives out on me again - THE DAY I GOT IT BACK FROM THE SHOP! No one
can seem to find out WHY this keeps happening - so my question is WHY DOES THIS
KEEP HAPPENING????? And has anyone else had this problem??? Granted, she does
have 137,000 miles on her now - BUT when it first started happening in 2010, the car had
maybe 60-70,000 miles on it. Any answers are much appreciated!

78 Answers

210,455

Something isn't right. Are you using new alternators or rebuilt ones? Maybe find another mechanic to check it out?

3 out of 3 people think this is helpful.
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Well, 3 have checked it out thus far and don't seem to find anything wrong. I believe the first two replacements may have been rebuilt. My understanding is the replacement in Feb. of this year was a new one - I could be wrong. Either way, it blows my mind that this will be the 5th alternator in a car under 10 years old.

2 out of 2 people think this is helpful.
58,465

Have they checked the ground,s from block, to frame,and to ecm all so,

5 out of 5 people think this is helpful.
56,775

Also, check the wiring that plugs into the alternator very carefully. You might have a bad connection inside the plug that can't be seen. Check the serpentine belt and tentionor. Be sure the belt isn't slipping. According to rockauto.com you should have a 135 AMP alternator in there. Make sure it's the right alternator for your Mustang. HTH. -Jim

2006 ford mustang. I bought a cheap OBDII Bluetooth reader from google for $10 an used the android app Torque to get the error codes.P0622 Generator Field "F" Control Circuit Malfunction and P1000. I replaced the battery and alternator still same error codes and check charging system. Just ordered a ECM from auto parts warehouse for $280. I think that is going to fix it.

80

I own a 2006 ford gt v8 mustang. 78,000 miles. Mines doing the same thing! Why? It only happened during really cold weather and is usually snowing. Check charging system error keeps popping up shortly after the car just dies. Replaced both battery and alternator. 1 month later ( today 12-25-14) same thing .... What's causing this and how the hell do I fix it???????

8 out of 8 people think this is helpful.
40

I have the same trouble, does anyone Know something about?

4 out of 4 people think this is helpful.
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Bought new my 2006. She has 110k milres. I replaced the alternater first 3k. my girls light comes randomly too now some times pproceeded by a bit of a shutter. Gage reads OK and accessories don't drain charge. My also seems to be in wet/ colder weather. She also is kept out doors. Help!

2 out of 2 people think this is helpful.
560

The problem may be due to poor grounds between the negative battery post and the alternator. The floating ground will cause the field voltage to be too low at times which will then not charge the battery and at times will also cause the voltage output to high (18 to 20 volts) which will damage the battery. I installed a direct ground between the battery to the alternator bracket bolt to solve the issue in my Mustang.

15 out of 15 people think this is helpful.

im glad im not the only one this Is happening to iv had 5 alternators and at least 3 batteries in 3 years mine just went out again today, but I made sure my last alternator had life time warranty.. you need it with the 06 models I have heard everyone complain about them..

560

please check the voltage between the negative battery post and the alternator. if this is not close to zero you will be in the same position shortly. I fixed mine by adding a ground strap between the battery post and the alternator bracket. I am a retired Chrysler engineer. hope this helps.

14 out of 14 people think this is helpful.
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just to be clear, If I install a wire between the negative battery post and the alternator bracket it will help to keep this from happening? Will this also fix a shudder that seems to happen if there is a couple accessories on at the same time (A/C, headlights)? What size wire should I use?

3 out of 3 people think this is helpful.
560

I pulled a ground cable off of a Dodge Ram in a salvage yard that was long enough. It already had the terminations at the ends for easy installation. A number 6 wire should do though. The alternator needs the field voltage to operate and the voltage regulator on the alternator uses the ground as the reference for the output voltage. The jumper keeps the ground to the alternator at the correct voltage. Poor grounds can lead to early failure of other things such as wheel bearings which are damaged by small arcing from the voltage differences between the drive train and the body. I cannot tell you the cause of the shudder without additional details. The engine controllers are usually designed to run at voltages as low as 8 volts and I think the engine would die shortly after the vehicle voltage dropped below that level.

7 out of 7 people think this is helpful.
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OMG!!!!!!!! I so thought I was all alone! Mine overcharges and spikes up to 17.6 volts!! 08 v6 pony/premium packages. Mine started just 2 years after I got her brand new. Had the issue ever since. Up to replacing the alternator 6 times and about 7-8 batteries! Going within months now instead of years!

1 out of 1 people think this is helpful.
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Well. I tried this. It did not stop my problem. It did however take it from battery needle going to high to only 3 quarters when it happens. Maybe bigger ground wire? I used a 6 Guage. Any suggestions? Anyone else have the same problem? Car will flicker headlights, map lights, tag light and it blows the blower motor resistor when it happens. Sometimes it have different symptoms. Alternator will overcharge up to 17.6 volts! And spikes randomly causing my ac to blow really hard and my subs to cut out along with blowing that resistor I mentioned before. Can anyone shine light on this? Mostly happens when coming to a stop or at a stop idling. Never happens while on the pedal. Give it gas when it happens and it stops doing it. I can't figure this out for the life of me. Check charging system light does not come on, no CEL either. Had ford test everything including the pcm and they say it's just fine. No codes. But obviously something is wrong. HELP!!!!! Or is this thread dead?

1 out of 1 people think this is helpful.
560

You may have very corroded ground wires on your car. Check the voltage at the battery while the car is running. Then while checking the voltage hook up a jumper cable from the negative post of the battery to the mounting bracket of the alternator. If the voltage changes then you need to still add a better ground.

3 out of 3 people think this is helpful.
560

Follow the ground wires between the battery to the body and the ground wires from the body to the engine. Clean all the terminations and make sure the bolts are tight.

1 out of 1 people think this is helpful.
20

I checked negative battery terminal to the alternator ground with a volt meter. Touching the negative and the case on the alternator I get a 0.034 at the highest. A little fluctuation but yeah. Positive side to positive lead on alternator I got .018-.020. Give the car some gas. Doesn't make a difference. Turn all electronics on. Doesn't make a difference. It charges normal, just spikes randomly up to 17.6 volts. Normal charge range is between 12.3 and 14.6 is what I see until it spikes. I will give my other grounds a good cleaning and what not today and see if that makes a difference. I'll also try the thing with the jumper cables. Any other suggestions? Was told my pcm could possibly be going out?

560

The Mustang that I was working on was a 2000 model. Yours might be different but I didn't think so. The alternator has a voltage regulator on the back side of it. The PCM doesn't have anything to do with the alternator unless the PCM has the voltage regulator built inside it. Later cars are sometimes built that way. The normal voltage should be higher than the 12.3 that you see. At 12.3 volts you are just measuring the battery voltage and the output of the alternator is probably zero which will lead to a discharged battery. Try the jumper cable when you measure the 12.3 volts and see if it doesn't jump to somewhere around 14 volts. Hope this helps. Steve

20

Thanks! I have no dying battery issues until it ends up killing a cell in the battery from being overcharged due to the spiking. But if it does I will then add a bigger ground wire. The one I'm on is an 8 guage. I'm going to try a 2. Also ford told me that my alternator does have a regulator. But that the regulator is PCM controlled. And that if the PCM is telling the regulator to charge so much then that's what it will charge. It won't charge until it's running because it's power is belt driven. But the pcm controls how much voltage the alternator puts out on my mustang. It's an 08 4.0.

look up how to do a full field test on your model. This will completely bypass the PCM and voltage regulator so that your alternator will run at full capacity during the test. This will help you eliminate the PCM or voltage regulator as the cause of the issue. Definitely do this before paying for a PCM!

560

if the pcm detects a low charge of the battery the voltage will go up to charge the battery after starting on a cold morning it is normal for the voltage to be high for awhile

1 out of 1 people think this is helpful.
560

it would take two number eight wires to be equivalent to one number six wire

1 out of 1 people think this is helpful.
80

I use to have this problem but i figured it out. I have a 2008 mustang GT premium that i bought brand new in '08. Not a problem until i reached 73,000 miles. I had this same problem and went through 4 alternators and 2 batteries.

3 out of 3 people think this is helpful.
80

But i figured out the problem and fixed it. It was the plug in the back of the alternator coming loose, losing connection, and going bad. I now have 133,000 miles and it just happened again.

2 out of 2 people think this is helpful.
80

I replaced the alternator and the plug and now 60,000 miles later, it happened again. That was almost 5 years ago. It was a good investment! So replace the plug and alternator and get back on the road. Lol.

3 out of 3 people think this is helpful.
45

I also have a 2006 Mustang GT 4.6L. When going to start the car, whether it sits for 2 hrs, 2 days or a week, it seems like the battery is low, I get the clicking like there is a loose connection and then it catches. It seems to happen more in the cool and cold weather that in the summer. I too have replaced the starter, alternator, and battery, to no avail. Ford has had it, a reputable auto mechanic I know has looked into it and nothing, Ford said it was fine, BS. I am now going to install the grounding strap between the battery and alternator and see what it does. Keeping my fingers crossed.

1 out of 1 people think this is helpful.
10

Did a Ford dealership work on any of your cars. This just happened to my son's car today and I just took it in. I replaced battery today and Ford says I need a new alternator. I am trying to preplan a problem. I am just a mom but on top of it. LOL

1 out of 1 people think this is helpful.
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I hooked up a 4-gauge battery cable (to act as a ground) from the bottom alternator mounting bracket to the negative post on the battery and so far no problems. Keeping my fingers crossed though, just in case. Ford worked on mine and said nothing was wrong and that they didn't detect anything at all.

2 out of 2 people think this is helpful.
560

I have never had any of my Fords into a Ford dealership. The service folks would have a hard time finding this issue. It took me some time to find the root cause myself. I am a retired Chrysler engineer that designed and developed many electronic components for Chrysler and Dodge. The alternator needs an excitation voltage to start working. If the ground is not present at the time of the testing the alternator will not have an output and the test will incorrectly show that you need a new alternator. hope this helps.

4 out of 4 people think this is helpful.
25

My 2006 V6 Alternator went out on me a little over a month ago. First the radio turned off, then the windows stopped working, headlights turned off and finally the car died. This was after about 4 months of the "Check Charging System" light coming on about every hour then quickly vanishing. Worked fine for a month, but today - first cold day after a month of 90-105 degree weather - the Check Charging System light came on roughly 6 times in a 20 minute drive. Ill clean all the ground connections and replace the battery tomorrow, but does anyone have any more thoughts on what it may be?

1 out of 1 people think this is helpful.
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T_Moore. You have the grounding issue that I have written about previously. You probably replaced a good alternator. You need to add the ground wire and not just clean up the grounds. This is really a design issue with the car that is easily corrected. You can quickly check this by using a jumper cable to attach the ground of the battery to the alternator mounting bracket and notice that the vehicle voltage returns to around 14 volts.

2 out of 2 people think this is helpful.
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Steven_M It is already at 14 volts. Today after the drive, as soon as I pulled into the driveway without turning the car off I tested the battery. It was at around 14.5volts. I revved the engine and it fluctuated a little, but stayed between 14.1 and 14.7. Turning the car off it dropped down to 12.5. I'm already planning on replacing the battery because it is almost 3 months old, and i'll replace the ground wire as you said as well. Still, it seems like at least when i'm parked the voltages is within the range of what it should be.

25

The battery is 3 years old*

1 out of 1 people think this is helpful.
560

I think what happens is that the designed grounds become loose and corroded and during temperature changes and vibration you loose the ground to the alternator. Once the alternator looses the ground the alternator field voltage is lost and the alternator quits producing power. This will lead to a discharged battery. If you can charge the battery and it will start the car it does not need to be replaced. The 12.5 volts that you measured is a good sign that the battery is acceptable. You should be able to hook your volt meter to the output of the power plug in the car. Tape the voltmeter so that you can watch it easily as you drive. When you notice the voltage going outside of the proper operating range pull over and hook a single jumper cable from the negative of the battery to the alternator bracket and see if the voltage goes back to normal. Hope this helps.

2 out of 2 people think this is helpful.
10

I have the same problem.. My car's voltage keeps rising and frying batteries..could the after market (paperformance 200amp) fix my problem

1 out of 1 people think this is helpful.
40

Look up electrical problems water getting in due to a leak in firewall have any of you had water spilling in through the dashboard. I just read about this and I I have also replaced battery and alternator too many times, I'm not a mechanic but take a look I believe it's related to this issue we are all having

2 out of 2 people think this is helpful.
40

I have been reading even more stories about this water leak getting in to the electrical, mustangs going dead while driving. Leaks causing major corrosion etc. We need to force Ford to take responsibility for this issue rather than saling us alternator and batteries when it all starts with this sealant leak putting water in the electrical box and more. Please read these stories and let's demand ford fix the problem. I did not spend this kind of money on my mustang to find out about this problem through other ford owners when they could have at least informed us of it themselves before our issues escalted to more problems, rather than buying batteries and alternator etc. Trying to find out what's causing these issues repeatedly to happen

2 out of 2 people think this is helpful.
10

I bought my daughter an '06 Mustang GT in May as a college graduation present. 65K original miles Dealership installed a new battery 2015. Drove it home and the check engine light went on. Code indicated it was a.cam sensor. Brought it back to the dealer and they "fixed it" Drove home again (about 150 miles one way) and again the check engine light came on. Called the dealer and they authorized a local shop to make the repairs and shipped a new alternator (Internet search by the shop indicated the cam sensor code often is an indication of a defective alternator. They replaced the alternator in June and all was good until this afternoon when a dash warning light came on indicating to check the brake system and the car would not start. AAA responded and checked the alternator which showed it was charging at 9.45 V. They got the car started but the power windows seem to be running slow so appears to be a shortage of electrical power. Does this sound like a problem with the ground as well? Sounds like an easy fix if that is all there is to it.

1 out of 1 people think this is helpful.
560

The slow window motors are a sure sign of low voltage. Not likely that a short would develop in the window motor system without taking out the fuse. The electrical system needs to measure around 14 volts when the car is running. When the engine is off you should measure about 12.1 volts across the battery. If you do not see this measure the voltage from the ground terminal to the bracket of the alternator with the car running. This should be about zero. If it is not you need to add the additional ground strap that I have written about above. I see in the above posts problems concerning the corrosion development and water intrusion issues that cause the need for the added ground strap and I think that corrections should have been there all along as Ford would have known about this from their environmental testing. But as these vehicles are all out of warranty we just have to deal with the issues as best as we can as they arise.

4 out of 4 people think this is helpful.
35

My 2006 has a Saleen Supercharger, Ford Racing Cams, Ford Cam covers, Ford Racing Headers, 40,000 coils and 39 lb injectors. The car has only 26,000 miles on it and is used mostly in shows. I only run it about every 3 months, taking it to shows and keeping it covered most time in garage. Cams were installed May '15 and shortly afterwards it started dying on start up and then shurtered when driving. There was a voltage drop noticed by speed shop and belt tensioner replaced with Steeda heavy duty tensioner. I installed a PA Performance altenator, just to get the original out because of it's appearance. I ran the car on streets and highway for about 30 miles with no issues, untill crusing at 60 mph and the shuttering started again. The other day I started the car and within one minute it died. Now it won't start. No solution yet as I am going to have it hauled to the speed shop to see if they can figure it out. I have not installed the ground mentioned from the negative side of the battery to an alternator bolt, but when installing new altenator, every metal part was very clean and no corosion noticed. I will install the negative wire just to be on the safe side.

45

Steven M - I added a 4guage grounding wire from the negative post to the alternator and I still have the problem with power draining and starting issues. The alternator is new, so is the starter. The battery is an interstate and about 2yrs old and fully charged. where can the power drain be coming from? My mustang is an '06 with only 13,000 miles on it and garage kept. I even had it at shop and they would put it on a computer overnight to see where it was draining and they couldn't find it. Ford said they didn't notice anything either. Almost ready to sell the damn thing and get something different, but the wife really loves the car.

35

Since mine stays garaged mostly, I always have it on a trickle charger to keep the battery from draining. I know with all newer cars you always have some electrical items running, such as the clock, alarm (if equiped), and mostly anything else hooked up through the system. I'm not sure if the ignition switch kills everything is why I say "mostly anything".

1 out of 1 people think this is helpful.
45

We shouldn't have to keep trickle charge on it. I keep my Ford F150 outside, including in the winter here in Alaska and it is fine. This is the first of many vehicles I have owned that does this. I have had some $200 clunkers in my life that would start better than this car. Steve M pointed out the negative grounding system is weak, but even after adding a grounding strap to mine, it is still the same.

56,775

On new and late model vehicles there is a constant drain on the battery even when the ignition is off. So if you do not use the vehicle on a regular basis the battery will go dead. I have 2 vehicles that I use infrequently and I disconnect the negative (-) battery cable each time I park them. A trickle charger or "battery tender" is another option for some people. My '70 Catalina, for example, never had a dead battery issue when I wasn't using it. This is because when the ignition was off there was nothing drawing power from the battery. No computers, alarm system, radio that needed power for a clock or presets. However those days are gone. There's always something "running" on today's vehicles long after they're turned off. HTH. -Jim

560

07 heritage, I don't know what could be the drain. Suggest getting a 1000 ohm resistor and putting it between the battery ground cable and the battery post. Measure the voltage across the resistor to determine the current drain. Then pull fuses out to see what may cause the largest part of the drain to go away. You should be able to find the short or defective part.

1 out of 1 people think this is helpful.

I have a 1996 ford mustang gt. Something is burning out my alternator as well. It's not spiking, it works when it wants to. It will be putting out 14 volts but then you shut it off get back in and it's putting out 11. I have exchanged 7 brand new alternators in the last 3 weeks. I took it to the shop and asked them to do a full diagnosis and they put in a new battery and laughed at me. Then I took it back less then two weeks later, told them its doing the same thing. They got back to me and said, oh, well the connectors were loose it running now. I get the car back and all the gauges aren't working and the alternator isn't kicking in. I bring it back, they said it's a blown fuse. I come back and they tell me, it's your alternator, gonna have to replace it again. So they did, again it was putting out 14 and then boom down to 11. All the cables seem to be fine and the grounds are all hooked up. Any ideas?

560

Tina, Sounds to me like a case of a floating ground. Please read my previous posts for details and solution. Steve

10

Thank you for the posts, i had the same problem. With charging system Error. I found a small break in the wire going to the alternator regulator. My part number was 1u2z 14s411 ta. 2006 mustang Gt. Its a 3 cavity pigtail for me. Finally i declare victory!!! $50 at the dealer. $10 on Ebay.

10

Update, after replacing the voltage regulator plug, 200 miles later guess what, Charging System light came back on. I replaced the remanufactured alternator with a new one from AutoZone. I'm sure that did the trick. I no longer have any spikes in voltage. The air conditioner does not Spike the lights do not flicker. Was the alternator all along. This was hard to track down because the alternator puts out the proper voltage of 14.1. What other forms said the diodes in the voltage regulator are junk. I took back the 5 week old Reman alternator to AutoZone and got a new one for only $11 more. If you don't see any more posts for me you know when it's fixed permanently lol. What a pain.

1 out of 1 people think this is helpful.
560

Sehunt, I think your problem will soon return. An alternator putting out 14.1 volts is not the issue. The spikes that you saw were probably due to a faulty ground between the negative side of the battery and the alternator bracket. I don't see how the diodes can be bad as you measured the 14.1 volts. The diodes don't go bad and then heal themselves.

1 out of 1 people think this is helpful.
5

I have been through the ringer with my 2006 Ford Mustang GT and the "Check Charging System" code. I have installed new alternators, new batteries, and have even replaced the alternator connector, which seemed to have done the trick. All was well for a couple months, until yesterday evening. As I was pulling into the garage from work, the "Check Charging System" code came back on unexpectedly. This morning, as I'm pulling into work, all of my electrical stuff cuts off inside of the car, but it was still running. When I parked it, I turned it off, and tried to turn it back on, and got nothing. Now, I'm here hoping that after reading this, installing aground wire will solve my issues. I'm extremely tired of this car and it's electrical issues, and the service department at Ford is of little to no help.

Okay guys please since we all have been through it. What is the first thing I should do other than replace the battery . Im Trying to fix it with out buying parts I do not need . I have bought a new battery & alternator is fairly new. Do I just buy the new alternator? & install that ground wire to the negative side??? 140k miles

560

Jcast36, First you figure out which parts, if any, are bad. Get a voltmeter, jump the car off to start it, measure the voltage at the battery. If you do not measure somewhere around 14.5 volts place one of the jumper cable wires between the negative post of the battery and the alternator bracket. If you now measure somewhere around 14.5 volts I do not think you need to change the alternator. If you can charge the battery and it holds its charge it is probably okay as well.

Steven M . I haven't yet tried the cable need to get a hold of a volt meter. As well my battery has drained the last 3 days as I type my battery is getting charged at parts store. Thanks for the response. Not sure how to go about issue on the battery draining...... bummer hoping to figure out soon

45

Steven M - I have added the 4ga cable from the battery to the alternator and my starting problem still exists. I have had the battery changed and tested, the alternator and starter are new. Could there be a ground in the plug on the back of the alternator?

560

Jcast36, Even a cheap Harbor Freight voltmeter will work. You need to know the voltages to figure out the issue. 07heritage, What is the voltage across the battery when the car is running? When the car doesn't start does it start slow like with a weak battery? When you jump the car off does it start quickly? Is the problem intermittent?

5

My power wire that runs from the back of the alternator to the positive terminal on the battery is fried and I need to replace it. Will an 8 Guage wire work? Going to buy that and crimp it to make a new one.

Yes im getting a volt meter today. What is happening my battery is going dead like no juice what so ever. I went & checked the battery thry told me it was no good. So I bought a new battery & was able to drive it 30 miles then my battery meter on dash started going down to where it was beyond low. I took the battery back in they told me that there was no juice left in the battery what so ever so had to leave it to charge again. My battery is being drained completely. 2 mechanics came & suggested to switch alternator.... Only thing that scares me it will happen after changing the alt.

Steven M. Plus when I jump it it will start but battery is low & car sound like it shouldn't drive so I just catch a ride .

35

kporterd, the positive cable has a "fuseable link" in it. If you look at the factory cable, not too far from the battery, there is a light blue section. This is the link. So, you need to make sure you have this or a fuse inline with the wire you're going to replace. American Muscle offers a new heavier gage cable with a fuse block installed. It's made by PA Performance, who also makes alternaters.

560

Jcast36. Let us know the voltages when the car is running across the battery posts. Check it with a charged battery. Also if the voltage is not around 14.5 volts attach a jumper cable from the negative battery post and the alternator bracket and measure the voltage across the battery cables again. Does the engine sound correct with a charged battery?

Steven_M, I have a similar issue that I'd like to get your opinion on. Went to start my 2006 V6 Mustang yesterday and had the gauges go kinda funny, the radio turn on, the CD player sounded like it was trying to switch CD's. When I turned the key further to start it, all I got was the loud clicking noise. Had to be somewhere so I took another vehicle. When I came back later and tried to start it again, the gauges and radio no longer worked at all and nothing happened when I turned the key. The battery was under 12v so I charged it to above 13v and tried again with no change in results. Headlights and dome lights still work and battery has held same charge for 24 hours, but power windows, locks, and gauges will not do anything. Thoughts?

65

I have had all the issues with my 2007 Convertible. I did legitimately lose an alternator due to it working so hard to recharge a constantly low battery, I replaced the alternator. My battery would still be dead if I let the car sit for 3 to 5 days. I replaced my factory stereo (I wanted Bluetooth anyhow) due to the Cd player chewing on imaginary Cd's, thinking that it was draining the battery, it was not, the problem continued. I do not drive my Mustang daily, sometimes it sits for 2 days sometimes for a week. After reading the TSB from Ford, I submitted and bought a $19 battery tender from Harbor freight. I plug it into the power outlet above my stereo each time I park the car. The tender keeps the battery topped off. I have had no issues since going the battery tender route, it has been about 9 months. Using the power outlet on the dash makes hooking up the tender a 20 second task, therefore I don't mind doing it. I put the tender on the ceiling above my car and the cable hangs down to the floor, I can reach out and grab it when I am parked, so I don't have to do anything when I get in or out. When leaving, I just unplug the cord from the dash and toss it out the window, it will be hanging there within reach when I return. I also have the water leak issue and do believe that the two problems are related. My car drips onto the passenger carpet from the SJB (Smart Junction Box) area. The SJB is a very common area for our cars to leak, once water gets in it is very hard to get it out. The moisture can move around causing different shorts at different times, making the problem very hard to trace. I keep mine garaged so I decided not to go after fixing the leak, from what I have read it can be a monumental task. I know that a battery tender is a Band-Aid and the problem is not fixed, but I pick my battles. For you folks that have to park outside, you may have to fix the leaks to ever solve this problem, until then these cars can eat alternators and batteries like pezz. Below is the Ford TSB on the battery drain problem: http://www.stangpit.com/wp-content/images/docs/s197-tsb/07-05-13.pdf Below is the TSB for the water leaks. I think they are related problems. http://www.acc.umu.se/~olsson/mustang/tsb07-14-06.pdf

2 out of 2 people think this is helpful.

In last 3 years I have put 5 alternators and 2 batteries on 07 v6. My wife went to 2 shops and dealer and they all said not charging at low rpm. I saw this post this morning and added additional ground from neg battery term to base of alt. Last night at low rpm meter showed around 12 volts and did not increase till around 3 thousand rpm. After additional ground it charges to 14 volts at idle. I used a battery cable that I had already. Thanks for posting this.

I have a 96 Thunderbird with (it sounds like) the same problem. While driving, the battery gauge suddenly drops substantially. It had done this before, about a year ago, but my husband fixed it....we thought. Like so many of you, he bought & installed both a new battery & alternator. This seemed to work until a couple days ago. Because I was soooo used to having to watch my battery gauge very closely so as to be as prepared as you can be when your car dies whilst driving, I just happened to notice the gauge acting very familiar by suddenly dropping for no apparent reason. Prior to my husband "fixing" it, I could keep it from dying whenever the needle dropped by revving the engine quickly either while in park, OR with my other foot on the brake. This would bring the gauge back up close to normal. This wasn't the case this time. When it started acting up AGAIN, he told me that there was something else causing it so replacing one or both again wouldn't actually fix it permanently. I should also add that my air conditioner / defroster had started acting weird a few months ago as well. While driving & using the a/c, it would suddenly STOP. I could still hear the compressor come on & feel a tiny bit of cool air through the vents although it wasn't being blown or forced out. The defroster did not force any air out either. Then, as fast as it stopped, the a/c would start working again. No rhyme or reason as to when or what made it start OR stop. I should also mention that water has been getting into the interior of my car from somewhere unknown for quite some time now. Other weird, electrical related things started happening recently add well such as my digital clock is not visible at all, my dash board, was either very dim, or one half not visible at all (at night). We both knew these things were probably related in some way. I know absolutely nothing about cars, how they work, etc. My husband is an electrician. After pondering what would cause this circumstance, and checking everything out with his electric meter thing, he came in to tell me that he was fairly sure the problem was a "floating ground". Not that I doubted him, (much) but I began searching the internet for similar stories, & more importantly, solutions for it when I discovered this thread. Upon reading these stories, and the solutions offered, I'm confident that it IS exactly the problem (floating ground) with my car. Basically he is going to do what Steven_M has been suggesting. He's working on it as I write this. Wish us luck!

Ok everyone tighten the hell out of the batteries I had mine tight I thought but no had to go tighter

I have an 07 Mustang V6 that recently got shipped back to me. I assume it had been sitting in the sun for about 2months straight. When I got it back and driving the "check charging system" indicator came on, A/C cut off along with all other electrical loads, battery spike to the High indicator. When I pulled over I noticed corrosion on the negative terminal as well as my less than 2 year old Optima battery bulging. At idle the battery indicator would sit in the normal position but as soon as I gave it gas, spiked to high. I drove it about 25miles to the nearest autoparts store. They replaced the battery, cleaned the negative terminal and I was able to drive it home about 300 miles away with no issue. As soon as I pulled up to my house, the battery spiked again. Took it to autozone for a battery/alternator test and it checked out fine. Thing is, I still had the same issues. Car runs fine, but I noticed whenever the A/C was on is usually when the issues would arise. Took it back to autozone and tested. They said the alternator was bad. Ford wants $350 for a new one, but recommended me to a place that rebuilds. I was told the diodes in the alternator were burnt out, possible issues with the voltage regulator and that was the reason why it was acting the way it was. Soon it should completely die. The last time my alternator went out was about 40k miles ago. I then got a rebuilt one and had no issues until now. I plan on taking it to get rebuilt tomorrow.

I have an 06 GT with a Shaker 500. I am not the original owner. I have the stock OEM battery that has died maybe 4 times in the last 2 years. I give it a jump and it usually lasts for a good while. However, I've been reading a lot about the Shaker 500 coming on and doing strange things when the car is off. I have read about a lot of folks who pull the fuses and the car responds beautifully. I've also read about the heat blanket that wraps around the battery ending up missing. For those who do not know, the heat shield keeps the heat in the engine bay away from the battery, as that can cause damage as well. Before you drop a lot of money into repairs, try these steps: 1 - Pull fuses for radio, give it a jump, wait and see. 2 - 26 bucks will get you a decent battery tender from Sears. 3 - New battery, grab the blanket too. May want to consider moving it to the trunk with a relocation kit if you live in warmer temperatures. 4 - Get Battery and Alternator tested at Auto Zone/Pep Boys/Whoever, and purchase accordingly. Buy NEW only. 5 - If you've replaced your Batt/Alternator within the last two years, then I'd suggest looking into your radio. Do a search on "Shaker 500 battery drain" and continue your search. 6 - Have a mechanic you trust check for improper grounding, wiring, DTC codes, FAULTS (different from codes) and if you opt to get work done, get warranties. Hope this helps.

560

ownastang, did they test the alternator on the car or on their tester? If they looked at it in the car and not the bench tester the alternator may be alright.

Steven_M, yes they used their battery/alternator tester both times.

35

So since my post 6 months ago, on my '06 GT, Saleen Supercharged, Saleen Shaker intake, Ford Racing cams, headers, 39 lb injectors and was 40K coils, TCP custom tune; I replaced the alternator with one of a better "show quility". I also at that time added a designated 6 gauge ground from the battery to the altenator. The tuner noticed the voltage drop on the original altenator prior to my replacing and added the ground. They also suggested adding a heavier positive, which I did. For me, it was discovered that the TCP tune was fighting the Saleen tune. Unlocking the code to change the Saleen tune was an issue because Saleen will not give the code to unlock the computer because of contractual agreements with Ford. I also noticed one of the plugs was burned more than others and that coil was brownish. So, I went back to the original 20K volt coils and new plugs. Fortunately, the tuner was able to locate a guy who used to work for Saleen and was able to unlock it and then install a custom tune using an HP tuner. Since this I have no issues and the car runs better than ever. This guy says with a modified setup that I should change plugs about every 25K miles. Bottomline; not sure what exactly solved the problem, but it seems to be okay now.

Steven_M, Took my alternator in today and pretty much had the whole thing rebuilt. Turns out the only thing that was working correctly was the rotor and pulley.The stator was bad, voltage regulator bad, diodes fried, rectifier bad. I think some of the issues were related to the bad battery. I've removed and replaced the alternator and so far everything seems to check out. Lets just hope nothing else is/goes wrong.

I've been having these same issues!! Replaced alternator a few weeks ago, and BAM she decides to struggle to crank when she does crank everything resets like the battery was dead no low voltage reading on the guages so today I take it to the shop that replaced my alternator they tell me its a bad battery so I go spend $130 on a new one! Its good right now, but I don't see this solving my problems for long!! HELP PLEASE!!! I have an 06 GT with very few small mods.

560

Please read all of my previous posts The voltages will read correctly when the resistances are low between the battery and the engine sometimes with vibration temperature and moisture the sources of the electrical breakdown occur I have thus far had to install the grounding strap which is described in my previous posts on 2 of my 3 mustangs

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Steve, I have installed a 4 gauge strap from the negative side of the battery to the mounting of the alternator with no solution to the problem. Battery is full, but yet starting problems and draining persist. I am ready to sell this POS. It is an '06 with only 14,600 miles and has been garage kept. No mods and no accidents at all. Otherwise a great car.

560

Do you have about 13.6 volts all the time when the car is running? If not there is still something wrong with the charging system. If the charging system is okay get a 1000 ohm power resistor and put it between your negative battery terminal and the negative cable hook up the voltmeter across the resistor if you have a short draining the battery you will see a voltage here a small drain is normal but you can start pulling fuses and see what circuits are causing the issue by noting the amount of change in the voltage reading hope this helps

To the one with LEAKS ON PASSANGER SIDE ; Open the hood and look close to the front. There are a small black rubber pocket on each side. Pull it out and clean it .Once clean reinstert back in and just periodically check for trash. Mine was full of mud and old leaves that had blown in the car. My husband found the pocket and solved my problems for the leaks.

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