Blower motor intermittent speed/ not working

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Microang
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Blower motor intermittent speed/ not working

Post by Microang »

Hi,

My car is having a strange issue which I cannot seem to find documentation on, basically the heater blower fan speed varies when on full (my car also has the only high problem) it just gets faster and slower and sometimes will not work at all, but turning left seems to make it work for a short time, this is very strange to me. Does anyone have any idea where I should look?

Thanks.
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hornhospital
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Re: Blower motor intermittent speed/ not working

Post by hornhospital »

Start by checking all the grounds from the chassis to engine and chassis to body. Turning left is loading a ground point that's being used by the blower as a path to ground. It may or may not be where the blower is supposed to ground.
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kevmills67
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Re: Blower motor intermittent speed/ not working

Post by kevmills67 »

Microang wrote: Wed Dec 13, 2017 6:22 pm Hi,

My car is having a strange issue which I cannot seem to find documentation on, basically the heater blower fan speed varies when on full (my car also has the only high problem) it just gets faster and slower and sometimes will not work at all, but turning left seems to make it work for a short time, this is very strange to me. Does anyone have any idea where I should look?

Thanks.
it has been a while, also depends on the year of your car, but, there is a blower motor resistor I think it was that is behind the blower motor that goes bad. Unfortunately, only way to get to it is removing the blower motor and to do that you are removing your center console, glove box, etc. Huge pain in the arse.
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PTFunk
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Re: Blower motor intermittent speed/ not working

Post by PTFunk »

kevmills67 wrote: Sun Dec 17, 2017 12:28 am it has been a while, also depends on the year of your car, but, there is a blower motor resistor I think it was that is behind the blower motor that goes bad. Unfortunately, only way to get to it is removing the blower motor and to do that you are removing your center console, glove box, etc. Huge pain in the arse.
It’s not a resistor but rather a transistor, either as part of the potentiometer behind the knob or underneath the blower assembly. The former requires disassembly of the climate control panel (a bit of a pain) and the latter is easier in that it requires just removal of the blower which is in the back of the engine department. I recently had the same problem and ended up changing both transistors, which are different types but can be easily sourced from eBay or online electronics stores.

Search for posts by Chris Wright since he goes into troubleshooting techniques for determining which transistor it likely is. It could even be a third transistor on the AC blower which is underneath the glove box. This is probably what kevmills67 is thinking of.
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