how do i know if my blower motor resistor is out also how do i know if the heater switch is not working

160

Asked by Dec 10, 2013 at 12:07 AM about the 2000 Mercury Grand Marquis LS

Question type: Maintenance & Repair

my heater and air conditioning not working nothing is blowing inside the car how do I find out which parts I need to replace (blower, switch, blower resister) please help It's cold for real

37 Answers

72,345

Unplug the blower motor. Using a 12 volt DC test light probe the plug for the blower motor. Turn the ignition to the run position and move the fan switch through all the positions. If this is a 2 way plug you may have to probe both sides of the plug since one side will be ground (-). If the test light lights up on all the positions, the blower motor is bad. If not, plug it back in and unplug the resistor block. The resistor block is usually very near the blower motor and will have a 5 or 6 way plug on it. Probe each hole and move the fan speed switch. The test light should light up at each hole when a different fan speed is selected. If so, resistor block is bad. If not, fan speed switch is bad. This is assuming that all the fuses are good. HTH. -Jim

46 of 46 people found this helpful.
2,085

There may be a bad relay for the heater motor. Check the fuse first.

19 of 19 people found this helpful.
26,225

Quick check: If the fan blows on HIGH only - the resistor is toast - the fan motor probably caused it. If the speed selector switch is sloppy in the dash, or operates the fan erratically - the switch and pigtail are melted - the fan motor probably caused it. If the fan doesn't blow at all, check the fuses, if ok - replace the heater blower motor - note: the blower motor and fan (squirrel cage) are often sold separately. If so, consider replacing the fan too - it's a little difficult to remove from the shaft and likely, is wallowed out or melted a little. If I had to prioritize the failures it would be: Fan motor, Resistor block (solid State BTW) and then switch. Getting a lot of these in our fleet right now.

88 of 88 people found this helpful.
90

Tracy...smh (up & down)...you definitely sound like you know what your talking about...no insult to anyone...you were all helpful.

9 of 9 people found this helpful.
26,225

Thanks! I've fixed a few cars in my 30+ years as a Tech.

20 of 20 people found this helpful.
110

Very simple to check blower if it has two pins connector: 1. unplug connector from the blower motor 2. just connect negative wire to one terminal and positive (12V) wire to second terminal of the blower motor. If blower motor spins....its mean it is good., Several vehicles' blower have two terminals.

11 of 11 people found this helpful.
140

I have a blower motor that stay on i have to take out the fuse to make it turn off

14 of 14 people found this helpful.
72,345

Sounds like the blower motor relay is stuck on. HTH. -Jim

10 of 10 people found this helpful.
Best Answer Mark helpful
160

I have a 2000 Nissan maximum blower motor want come on. Checked motor it works what could it be

16 of 16 people found this helpful.
980

2002 marquis i just replaced the blower motor and the climate control panel and the heat still doesn't work but if you straight wire the blower motor to the battery it will work what can that be

98 of 98 people found this helpful.
70

I have an 07 Nissan Altima. I'm in WI (so very cold winter temps) and my heat isn't kicking in for 20 minutes or so when it's really cold (negative temps - 20 degrees- ish). If I'm at work and it's sitting outside all day, it takes the 20 minutes to warm it up. If I'm at home, and my car is in the heated garage.... there's no problem. It heats up right away. A friend of mine is a Mechanic and thinks it's the resistor. In this make/model, the resistor is an all in one with the blower motor. It seems like the blower motor isn't the issue, because when it finally turns on, it works great, on high or low, feet, face etc. What else could it be? Relay? Please help :)

7 of 7 people found this helpful.
72,345

Sounds like the thermostat. HTH. -Jim

1 of 1 people found this helpful.
10

connector plug wire has no fire to blower motor what do i do now

1 of 1 people found this helpful.
72,345

Unplug the resistor block and check for power there. At least 1 wire should be hot with the ignition on. If that's dead unplug the fan switch. Again, one wire should be hot with the ignition on. I'm assuming that you've checked the fuses? If the switch is dead check for power at the relay. If you've got power at the relay tap it. It may be stuck. If tapping it doesn't get the blower going replace it. They're cheap. HTH. -Jim

6 of 6 people found this helpful.
135

Just replaced the resistor. But it still only blows on 4. Is it possible that I got a bad resistor? Is there a way to check it?

13 of 13 people found this helpful.
26,225

It's possible that the resistor block is bad but more likely that the switch is burned out in this case.

6 of 6 people found this helpful.
120

I have a question.... I have a 2007 Dodge Nitro. my air conditioner stopped blowing completely. I replaced the resistor and still NOTHING. Straight wired the blower motor and it worked like a charm. ANY SUGGESTIONS?????? Oh and checked the fuses......

10 of 10 people found this helpful.
72,345

Blower motor switch on the dash or the blower motor relay. HTH. - Jim

5 of 5 people found this helpful.
50

I have a question I have a 2010 jeep liberty and when I push the recirculator button on the a.c. it's does not change the speed of the air coming out.. But u can hear I guess like it's kicking in under the dash it's a loud muffle sound but the speed doesn't change from when it's off to when it's on.. I need help on finding out what is the problem please...

5 of 5 people found this helpful.
70

Tracy, Very good advice. I got a mind boggler for you. I have a 2003 subaru forester that has low air flow when i try to use the heater or ac. It has NO cabin filter. Blower fan turns on and increases speed when i turn the air flow from 1 to 4. However, this whole time there is very little air coming out of the vents. I can feel heat when the heater is on and cool air when the ac is selected, but still.... the air flow is very low... I can barely feel it while holding my hand up to the vent. I checked inside some of the duct work and it looks clear... just dusty... Any ideas?

7 of 7 people found this helpful.
20

check ur fuses and relays first same problem just a relay

2 of 2 people found this helpful.
180

I have a 2003 cadillac escalade. I checked my blower motor by hooking it up to battery it came on and my resistor was tested with a fuse tester one side lit up .. no fire is coming from my hornets that connect to the resistor.. can someone help ?

7 of 7 people found this helpful.
180

Where is the blower motor relay located on 2003 cadillac escalade ?? Is it on the fan ?

11 of 11 people found this helpful.
70

I have a question: i have a 1998 dodge ram 2500 dodge ram cummins. The blower works when i have the key to accessory but when i start it it shuts off untill i drive down the road a little bit and then it works untill i shut it off, any suggestions?

7 of 7 people found this helpful.
120

Hi I have a 2005 Chrysler pacifica ac just stop blowing.. Not sure what I should or need to do. Please help. Thanks

12 of 12 people found this helpful.
50

I have an accord 2008.there is no much heat when the mode is on blow front and on this mode when i put the fan to HI i just get some luckwarm air but as soon as i change the mode to front+ bottom i start getting good hot blow as it is supposed to be. What seems to be the problem?

5 of 5 people found this helpful.
50

I have a 06 Honda Odyssey my front blower would not blow at all although my back slower work I spent weeks trying to figure out what was the problem only to find out it was the heat resistor pack autozone has one for $45 its a real easy fix two screws 1 wire pack with 4 wires located underneath the glove department now all my air worked perfectly anybody with a Honda Odyssey with little or no air running through your vents before changing out your blower motor should look into that piece before

2 of 2 people found this helpful.
30

I have a 2008 Scion XD and my fans were working at first then 1,2,&3 stopped and only 4 was working but yesterday 4 stopped working how do i know what the problem is?

3 of 3 people found this helpful.
50

Amanda If high worked like you said but now it has quit working your problem is heat resistor pack. I had the same problem on my Honda. It worked great then one day it would only work on high......me not thinking anything about it a few weeks later it stopped working all together.....i replaced that part now it works great.

2 of 2 people found this helpful.
50

Amanda it you take your car to a dealer ship or a auto mechanic shop you will be looking at 3 to 6 hundred dollars to fix your car best thing to do is to on YouTube and watch a video on how to do it yourself it should take no more then 30 minutes for someone who has never done it before to remove and replace that part also if you go to autozone you should be able to pick up the part for no more then 50 dollars. I hope that I have been helpful to you

1 of 1 people found this helpful.
20

I have a 2011 Kia Sedona. Sometimes when i turn on my heater- only the back is blowing out heat, the front and middle section of the van isn't blowing out anything.This happens for a few days and then it works and then goes back out. I have two heating dials- one that controls the back and one dial that controls the front and middle sections (1, 2, 3, 4 speeds). My mechanic says blower motor. He also said the pigtail is burnt which is the result of the blower motor problem. Thermostat looks to be fine- and when the blower does work i have heat. Does this sound right?

2 of 2 people found this helpful.
100

Tracy or anyone- i have a 1999 crown vic police interceptor. heat/ac sounds like its coming on but wont blow in any positions. Is my problem the blower motor resistor. i believe it is but want to double check. thanks

10 of 10 people found this helpful.
20

can anyone please tell me where is the blower motor resistor located on a 2003 subaru outback? I replaced the blower motor but still not work.

2 of 2 people found this helpful.

can any one help i have a vauxhall meriva design 05 plate when you put the heaters on they come on for a bit then go of then come back on again

10

My blower motor fan comes on about 1 out of every 10 times. It just seems like it is sticking. When it doesn't start I just hear a slight click. This happens for all speeds. I can start the fan manually with a chop stick and it runs fine and air is cold. Fuse is good. Any ideas?

1 of 1 people found this helpful.
26,225

The blower motor needs to be replaced or you have a wiring problem. Most likely - the blower motor.

120

I took my control panel off and there was corrosion between the knob and where it connected. scrapped it off and just like new. it was only working on high then it went to nothing working. but that fixed it

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