Just replaced the blower motor and resistor for the third time in a year. I've replaced the sub harness and put in a new control unit. It works fine for a while then once in while I smell burning plastic then after a few times of this the fan speed oscillates on its own. No connector is melting so the smell is either the resistor or motor toasting. Eventually the motor completely dies. No codes show on the self diagnostics. I've even disassembled the dash to inspect all of the harness connections but didn't find anything wrong. Any suggestions?

 

Where are you getting your blower motors? Are you getting any water intrusion that could get to the bearings? Are your cabin air filters clean? This is not a real common problem. If nothing else, I'd try a different brand blower.

 

The first two were OEM. Factory parts. The latest is an aftermarket because I wanted to see if it made a difference. No water coming in. Blower connection burning is a common problem for the original installation but it is suppose to clear up once the sub harness and burnt parts are changed. I don't know what else to do.

 

What I meant was that repeated failures are not common, especially if you're using factory parts. At this point, I got nothing.

 

The only thing left is to replace the climate control unit. The climate control unit tells the power transistor how much power to send to the blower motor.

The other thing is maybe a bad ground at the blower motor or the blower motor harness ground G401.