Batteries draining down


Asked by TruckerPaul2 Jan 22, 2012 at 02:25 PM about the 2000 Ford F-250 Super Duty Lariat 4WD Extended Cab SB

Question type: Maintenance & Repair

The batteries drain down after the truck sits a couple days. Batteries are only 3 year
old Interstates. Took it to my regular shop and they said the ECM was bad and
replaced it. But the problem is still there. As long as I use it everyday it starts fine,
but leave it for a couple days and the batteries are down too far to start it

22 Answers

Rey Gomez

Try cleaning up all ground points. I had something similar happen to me in a Taurus I use to own. Hooked up all new ground wires and moisture sealed them after with a rubber compound. Not sure if this will be the same situation as yours but it's a starting point. Power flows to ground and then back to positive.

4 out of 4 people think this is helpful.

Thanks, I'll try that. What makes it tough to find is that It worked just fine for 4 days after they replaced the GEM module ( not the ECM), but then it started its problem again. So I took it back to the shop, but it started just fine for them after it sat there overnight. And they say they tested it and can't find a draw anywhere.

4 out of 4 people think this is helpful.
Joseph Anthony Gahol

check your distributor if it is working...right after you start the engine, positive charge powers everything, now if its not distributed properly, the charge will drain the battery completely because its getting power directly...

11 out of 11 people think this is helpful.
Best Answer
Joseph Anthony Gahol

if that is happening then my advice is dont use any electronics while you are driving... that kind of heavy duty engine will only run a few kilometers then the battery dies out...

2 out of 2 people think this is helpful.
Rey Gomez

I would start replacing ground wires to anything electronics then in the engine bay and upgrade your negative battery wire to a 1 gauge. That seems to be the area where power is discharging. You should find all the braided wires and replace them but clean all the contact points first and ensure a good ground.

1 out of 1 people think this is helpful.
Joseph Anthony Gahol

yeah but what happens if there is still no ground and the battry is losing it's power? happened to mo once, so i was jumped with a different battery and when i started only the headlights were on (night driving home) and no A/C or radio... my car ran barely 3-5 km then engine went dead again...

Rey Gomez

Well, electronics and battery drainage are a bitch to diagnose my friend. I've had my share of them over the years and it takes a real smart mechanic to really find and diagnose the problem. If you can find a Ford shop with some top notch mechanics, I'd go there and let them have a go at it. They may have to have your truck for a week to really find the cause of the problem though. So maybe you can arrange a loaner from them.

2 out of 2 people think this is helpful.
Joseph Anthony Gahol

i agree...besides only the shop mechanics have the equipment for that kind of problem...someone with a know-how on car eletronics would be a big help too...


Thanks for all the ideas. They've had it at the shop for a couple of days now and can't find a draw anywhere and its holding a charge fine. So whatever it is its happening intermittently. which makes it even harder to find.

2 out of 2 people think this is helpful.
Rey Gomez

Well you have to think back as to when this anomaly starts occurring and the shop has to try and duplicate it. Was the truck sitting out in the rain or heavy downpour for instance before you drive it around. We're you going offloading in mud and muck or just driving urban roads. Just some ideas to think about.

3 out of 3 people think this is helpful.
Rey Gomez

Hi, Did your mechanic/ shop finally figure out what was draining the battery?

2 out of 2 people think this is helpful.

you might want to disconnect the ground cable from your battery then put your battery charger on it to bring it up to full charge then re-connect the ground cable. If your battery is reasonably good and you start / drive your vehicle reasonable distances every couple of days, it should hold. If you only use your vehicle every few days, do lots of short drives, stopping & starting, it could drain your battery. The alternator is a "battery maintainer", not a heavy duty battery charger. Hope this is useful...

Faye Cutchens

Not offering a solution, just want to share what happened with my car. The driver's side window power motor stopped working so I had it replaced at the local Ford place. When I got it back, if the windows are set on a certain setting (to go all the way down or up with only a slight short touch) it will drain the battery but if I use the setting where you have to hold the button down to get the window up or down, it does not drain the battery. Have no idea whats wrong but I do know for a fact that it is that certain setting on the power windows that drain the battery. I don't use that setting so I just keep it turned off.


Mechanic found that there were some marginal cells on both batteries and said it could only be fixed by replacing both batteries. I bought a bobble tester and found 4 of the 12 marginal even though after charging both, they read 12.8 and 12.7 after charging. After 3 days, voltage was drained.


I am currently having the same issue. I have an 2003 F250. They can not seem to find anything wrong. It started happening after i had my Gauge cluster replaced. My gauge cluster, power windows, power locks, and radio all stopped working. I got that all fixed and now the truck dies after about 20 minutes.

2 out of 2 people think this is helpful.

i have the same problem and after lots of time trying to diagnose the problem i figured out it was the ecm and the main harness plug had some corrosion, i figured it out by grabing the main plug and moving it around while running and it shuts off, im still trying to figure out how to clean the female part of the harness plug,

Bryan Maples

In my 01' F250 V8 5.4L Triton I was showing a pretty strong, pulsating draw off the battery. Fuse was showing it was the multi function switch (turn signal/wipers) piece so I replaced that and then it was still showing. Unplugged the radio during trouble shooting... and the RADIO with the key off, and the radio off, was causing the power drain. Not sure how common this is but may help. It was also triggering a clicking sound coming from where the headlights are turned on and off (the illumination of that dial and the radio share a fuse).

2 out of 2 people think this is helpful.

I am having a similar problem right now as the battery is being drained while sitting up. In my case, I have had electronics training and I can tell you that most of these solution replies are worthless. That seems to be the problem with searching for solutions anytime now. Answers like scrape the terminals, take it to the dealer, etc show that this is worthless information and only makes the problem solving more difficult. In my case it is caused by a malfunction in the AC circuits. I like most drivers will drive up to a parking place with my AC, Heat, etc on and blower motors running. When I turn off the ignition it kills everything and I don't bother to shut off the AC switch etc. After one of my battery failures and when I hooked up the charger my AC blowers came on. Ignition switch off. I found that I had to turn the AC Select switch off to charge the battery. It worked somewhat. A repairman replacedone of the AC Relays and it came on once but then cleared up. Now it has happened again. This time both the fan speed switch was in the on position and the AC select switch was also in the on position. I turned both off, chugged the battery and everything tests out working. Until I find the problem I will have to make certain that I don't leave these switches on when leaving the vehicle. As you should know, all of the devices powered up by the ignition switch are not powered through the switch The switch only supplies voltage to energize a relay, You have relays that have 12 volts applied to them all of the time. If they have to remain on then they have a set of contacts called latching contacts. That relay will stay on until the power is released by the lathing contacts. I am reasonably sure that I have a set of sticking contacts in a latching relay. To make it a little clearer think of your starting current. It couldn't possibly carry that current. Instead your battery cables stay connected to your starter all of them time. The positive cable goes through an open solenoid . This is nothing but a big relay. The ignition applies 12 volts to the primary and this energies the solenoid contact which allows the full battery current to get to the starter. Now in reading all of this I find nothing to help me with my problem but I can see that most of the problems here are most likely caused by relays are sensors. Hopefully a mechanics code reader might find the problem. If you can get to your local library, most of them now carry Chilton's On Line and there you can find the circuit diagrams and may be able to trace the voltage paths to and through the trouble site. The code readers are wonderful when they work but sometimes you just have to go back to the past and do some old fashion trouble shooting with volt meters and trouble lights. I will continue to search for my problem in the hopes that I might find where someone has the same identical problem and they can advise what their solution was.

6 out of 6 people think this is helpful.
Ross Cooper

Check your injectors. I had one bad injector and my truck would not start. I'd only get a couple of cranks out of it and then I had to jump it

Rey Gomez

Just reread your answer, it sounds like you have a moisture leak coming onto one of your electronics. If you have a cracked windshield or a leaky one, moisture could be dripping down onto one of your relays or electronics. I had a explorer with a cracked windshield go right down the middle so it wasn't really noticeable. My power windows stopped working after a while and I even changed the relays. After a very long time and much head scratching, me and my mechanic tore the dash apart and traced every single wire and finally found a set of corroded wires next to another relay box.

4 out of 4 people think this is helpful.

But as long as its running the batteries are charging an everything is working properly. The batteries only drain down after it sits for awhile and then it only does it once in awhile. And its a 7.3 Powerstroke desiel.

13 out of 13 people think this is helpful.

I also have a 2003 F 350 king ranch 4x4 7.3 L Turbo diesel and same problem. It acts like one phase is out on the starter and one battery fails tests. I'm pulling the starter to check it

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