I have a 2001 Impala. A while ago my AC/Heather Controls 1-4 would work and not 5. About 3 months ago controls settings 1-4 did not work and only 5. Every so often 5 would cut in and out. Just 3 days ago setting 5 stopped working all together (Now none of the settings work). This happened once before then setting 5 started back up again. When it works, it works really good. I have done my research online and I believe it's the Motor Blower Resistor, does this sound right? I can buy it at AutoZone and install it myself. Although, I would like some opinions before I try this. Thanks!

 

Could be the blower motor resistor, but when they fail they tend to only give the highest and/or only the lowest speeds nothing in the middle. You could have a bad blower motor. And it cant ramp up or tone down in response to the switch because its bad. Anyway, they are both in the same place. Usually 3 tiny screws to a cover and the things flops right out. The resistor is in close proximity to it with 2 tiny screws holding it in also.

 

Install new resistor.Hi fan uses 12 volts that does not go through resistor.All other
lower speeds step down to lower voltages. I've had this happen to me. oldphart.