Blower motor fan speed selection switch not working

Jaxon B.

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Aug 11, 2020
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170
Location
West Palm Beach, Florida
So, about 2 days ago my HVAC cluster went from working perfectly to not having any fan speeds at all. I've had this issue before and I thought that it would kind of just fix itself like last time, but this time around seems to be a little different. 3 days in and no blower. I don't really even know what to check.

I read that there could be a bad ground somewhere that would stop the fan from working, and I think I have something to support that, behind the instrument cluster there is what looks to be a loose ground wire connected to the body but loose on the other side. It is Mopar branded and has that weird orange/yellow foam stuff around it that the temperature selector cable has.

I don't have a power station or anything to try to feed the blower 12 volts, and I don't think the relay is bad. I recently replaced the resistor (like 2 months ago) and the cables going into it are just fine, not melted. Matter of fact, all cables seem to be not melted.

Any help on diagnosing this would be awesome. I hope it's not the whole HVAC cluster, the slider-control style ones that I have are so much more expensive than the dial controls. Am I able to replace just the selector switch? It seems like it would come out easy.
 
So, about 2 days ago my HVAC cluster went from working perfectly to not having any fan speeds at all. I've had this issue before and I thought that it would kind of just fix itself like last time, but this time around seems to be a little different. 3 days in and no blower. I don't really even know what to check.

I read that there could be a bad ground somewhere that would stop the fan from working, and I think I have something to support that, behind the instrument cluster there is what looks to be a loose ground wire connected to the body but loose on the other side. It is Mopar branded and has that weird orange/yellow foam stuff around it that the temperature selector cable has.

I don't have a power station or anything to try to feed the blower 12 volts, and I don't think the relay is bad. I recently replaced the resistor (like 2 months ago) and the cables going into it are just fine, not melted. Matter of fact, all cables seem to be not melted.

Any help on diagnosing this would be awesome. I hope it's not the whole HVAC cluster, the slider-control style ones that I have are so much more expensive than the dial controls. Am I able to replace just the selector switch? It seems like it would come out easy.

This is a pretty easy and cheap fix. check out this video.

 
This is a pretty easy and cheap fix. check out this video.

Just watched the video, I didn't know it was that difficult to change the resistor on the later models lol. I just changed mine so I don't think it is the issue but I have about 1 or 2 spares that I can try just to be sure. I saw in the beginning he had the actual switch, where can I find that (part number?) Just looking up "blower motor selection switch" gives people diagnosing it. Is there a way I can test it to make sure that is actually the issue. The FSM is confusing on this topic.
 
If it's the selector switch you should be able to pull it out of the dash and jumper the connections to test if the fan turns on. Of course I've never seen the back side so maybe you can't.

ETA. It looks like you can test it. It's $50 so I wouldn't replace it unless I was sure.

https://www.ebay.com/i/352905997248...d=link&campid=5337789113&toolid=20001&mkevt=1

It might cheaper to buy the whole control unit if that's it.
 
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If it's the selector switch you should be able to pull it out of the dash and jumper the connections to test if the fan turns on. Of course I've never seen the back side so maybe you can't.

ETA. It looks like you can test it. It's $50 so I wouldn't replace it unless I was sure.

https://www.ebay.com/i/352905997248...d=link&campid=5337789113&toolid=20001&mkevt=1

It might cheaper to buy the whole control unit if that's it.
Looks like you can remove control panel & put a jumper between the connectors to see if the fan spins.

Jump from pin C on connector C3 (red/green wire) to pins A, B, C, or D on connector C1.

1623935220648.png
 
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Pretty common for the blower motors to fail. If you've replaced the resistor I might just pull the motor, it isn't too difficult. It's probably a rusty corroded mess filled with leaves.

(as the motors reach end of life they come to rest in positions where the brushes don't make contact because it's all burned to hell, a bit of shaking and air flowing moves the cage a bit and it works again for awhile, your description seems to match that too)
 
Did you check fuse #8 behind the glove box?

If that isn't it, use a voltmeter and the circuit diagram that Qslim posted above and trace out where the power stops.

A meter can also be used to quickly check if the ground to the motor is good.
 
IF you do not know how to use or have a Digital Volt Ohm Meter you need to either purchase one at Harbor Freight or have a friend come over that know how to use the meter and start doing some trouble shooting searching for where the voltage stops. Just use the drawing that QSlim posted above instead of guessing and throwing parts at the problem.
 
Pretty common for the blower motors to fail. If you've replaced the resistor I might just pull the motor, it isn't too difficult. It's probably a rusty corroded mess filled with leaves.

(as the motors reach end of life they come to rest in positions where the brushes don't make contact because it's all burned to hell, a bit of shaking and air flowing moves the cage a bit and it works again for awhile, your description seems to match that too)

It's probably packed with leaves and dead rodents. In Florida, maybe a snake or gator.
 
It's probably packed with leaves and dead rodents. In Florida, maybe a snake or gator.
When I changed my heater core a few months ago I removed about a cubic foot of nesting material.
 
Oh wonderful PO, cut out the original connector for some reason and this is how my blower is connected apparently
1491874e-432f-47c2-a61f-79674f6ccd43.jpg
e1fd0b55-acd8-43e7-bae1-be06d67428b8.jpg


Jumped it manually, does not work, tried both polarities. Guess i'm heading to autozone to buy a new one. I tried jumping the switch with wires but no cigar.
 
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Ebay can be really cheap as well with shipping included. Just do the buy-it-now, cheapest with shipping sort and you are good to go. Glad you found the issue and didn't find any critters in there.
 
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Also, with the selector at full speed I was reading about 3-4 volts on the blower motor connectors, is that normal?
No. At full speed, all the resistors should be bypassed and you should get a reading of 12 volts to ground.

When you say you "jumped it manually" do you mean you hooked the two motor terminals straight to the two poles of the battery?
(Your picture just shows a grey wire going from one terminal of the motor to the other.)
If you haven't done that, I would before I replaced the motor.
3-4 volts would barely be enough to turn the blower if at all.
 
No. At full speed, all the resistors should be bypassed and you should get a reading of 12 volts to ground.

When you say you "jumped it manually" do you mean you hooked the two motor terminals straight to the two poles of the battery?
(Your picture just shows a grey wire going from one terminal of the motor to the other.)
If you haven't done that, I would before I replaced the motor.
3-4 volts would barely be enough to turn the blower if at all.
Yep, that's what I did. Just fixed it, give me a second to post what happened.
 
I fixed the issue, while the blower motor was bad, after buying a new one and testing it, it still didn't turn. Figured that 12v is what it should have so my dad and I poked around with the voltmeter and found that, if you put one lead into the positive wire and one to the negative pole on the battery we were getting 12v but were not getting much of anything if the negative lead was on the negative wire going into the blower motor.

Come to find out, the blower motor as well as the ground was bad. Made a new ground wire and now it blows perfectly!

Thanks for the help everyone!
 
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