I have a 97 blazer w/ a 4.3 Anyhow heres my issue.. My heat/blower motor will only operate on speed 3 or medium/high I guess you can call it. If the speed control is turned up to 4 or down to a lower speed the blower motor turns off. I have replaced the blower motor resistor and blower motor speed control switch. I dont have access to a test light or other test equipment at this time. What else could I possibly replace to fix this? I wouldnt think it would be the blower motor since it does run on speed 3 but I could be wrong.

 

I would think it's the blower motor.