I have a '97 Blazer 4 door. The blower motor (when working) starts out strong and over a period of 35 minutes slowly fades out to eventually not working. I tried pounding the dash and that didn't work. Every once in a while if I hit a bump it will go back on but most times it does not. Anyone know of a solution? I am thinking there is a loose wire somewhere?

 

If the blower motor doesn't work on any speed, it likely is worn brushes in the blower motor itself. If this is the case, the motor likely needs to be changed.

 

same truck same problem it is the blower motor

 

I had this same issue for some time. Check your ground wire on the fire wall coming from the blower motor

 

Im having the exact same problem, Comes in then goes out, hit a bump, comes back in. Now it quit working all together. I was wondering if you could tell me how to test it to make sure it has power? where is the ground wire on the firewall so I could check that?