Hi, I wonder if anyone else has had this problem? WhenI first start up the Blazer in the morning the blower works fine on all speeds, if I stop and shut off the engine, like at the gas station when I start it up again "sometime" the fan will not come on again, while driving "sometimes" the blower will change speed, slow down and then speed back up again
and "sometimes" it will quit running at all. I have checked the wiring and connectors and dont see any problems, I bought a new blower motor and have not installed it yet because Im
wondering if the problem could be in the resistor or the three relays next to it, it seems more like an electrical issue as opposed to bad brushes in the motor.
Any help would be great, Thanks!

 

My guess would be corrosion in the resistor.....only a guess.

 

If it is happening on ALL speeds then it can't be the resistor, because the system has a high speed relay and doesn't use the resistor for high speed operation. I would wait till it happens again and disconnect the motor. Then plug in a test light across the motor connector if it lights then you know it's the motor if not then it's probably a wiring problem. My guess: it's the motor.

 

Thanks for the advice, I'll test the motor as suggested...whatever the problem is its a pain in the *** in the middle of winter here in Washington State, I already have a new blower and I think I'll go ahead and replace the resistor as well maybe even the relays.
Thanks again!

 

had a similar problem - changed the resistor, no change, replaced the motor and the problem is fixed - seems the shaft on the motor gets to sticking and the starting torque of the motor isn't strong enough to overcome the inertia.

A real bitch of a job - you literally destroy the outer plastic shroud to get to the motor - take out the ecm and overflow tank to get to it - about 1.5 hours if you have the part.

 

Thanks dashyman...diving into the blower replacement tomorrow, will report on the outcome...if I survive...