New to this forum. Ive been working on my fathers old 96 blazer RWD. ive been tracking down a problem in my ac system. My blower motor will not blow any air on any speed. ive tried hooking a new blower motor up thinking it was just a bad motor from sitting up for over a year. New motor didnt work. Checked fuses and used a multimeter on the harness into the blower motor. This is where i get lost. On the purple wire i get a fluctuating voltage depending on where the fan speed switch is located. On full blast i get 12 volts on both sides of the harness. My impression is that i should have 12 on one side and the other be the ground.

 

Update. Blower motor is good jumpered from battery to motor works fine.

 

Nevermind found the problem. Dang Squirrels ate up some wiring. Got it all fixed!

 

My '95 S10 does the same thing, but I don't see any sign of squirrel damage to the wiring. Sometimes the blower motor comes on (usually when I don't need it) and other times when I need it, it won't come on. I have checked the wiring and connections, I changed the blower relay. I am having trouble with the blend door not operating properly. I replaced the broken actuator motor, but it still doesn't operate. I know it is old, but so am . Any suggestions would be appreciated, very much. Thank you.

 

I ended up snipping the ground wire and running a ground straight to the frame. Might also want to check the resistor. It's just to the right of the blower motor and evaporator. I know my resistor is bad but any air is better than none lol. Might be the rheostat in the dash going bad but those are few and far between on that.

 

Honestly it sounds like the dash controls are going out but that's usually the last thing to go. Try looking at eBay sometimes you can find the whole assembly for $50 and if that doesn't fix it put it back on eBay haha