2002 Chevy Blazer- drove all over town with AC on, all was fine. Went out an hour later, blower won't work on any speed. Ac compressor still going and cycling normally, just no fan to push the air. So, tested every fuse I could find, manual doesn't list a blower fuse. Replaced Resister board, no change...replaced blower relay...no change...I have 12 volds at the blower relay...and 12 volts at the resister board...but at the plug to the blower motor, I have no voltage at all.....I don't know where else to go from here. It's never given any trouble before...anyone have any suggestions?

 

When I got tired of my fan not having two of its speeds I replaced the resistor That doesn't sound like your issue but maybe..
Tere's some other ideas if you scroll to the bottom of the page.

 

Lets simplify the diagnosis and use the high blower motor setting for now since that bypasses the resistor network. I am assuming manual AC.

There are 2 fuses involved so check:

HVAC fuse 9 (20A) in the I/P fuse block on the left side of the dash
HVAC fuse (30A) in the underhood fuse block

On high blower do you have 12V at the 86 blade in the relay socket? It is fed by an orange wire from the HVAC module.
Do you have 12V at the 87 blade of the relay socket? That is fed by an orange wire from the 30A HVAC fuse in the underhood fuse block.

We will go from there.

George

 

I don't know if this will help but my blower motor used to stop working or just go in and out. I ended up just moving the entire wiring harness behind it around until I found a position where it would stay on and then zip tied it into place. Haven't had a problem since.

 

Similar. Mine runs "intermittently". Wiggling the wires gets it to run if it doesn't.