Very strange A/C problem

[cjp1280]

My truck is possessed. I have no high speed blower, all other speeds work ok. When a/c is on, the rear blower cuts out. Rear blower only works when the switch in the front is "off". I have replaced the control unit in the front, thinking the speed selector switch was bad, but it's doing the same thing. Is there a control module somewhere that could be bad? I'm stumped...

 

[TheJackal]

There is a separate relay that bypasses the resistor and provides full power to the blower motor when it is turned to "high." It's possible the relay isn't working.

I'm not sure what could be causing your rear A/C problem, tho. It seems like it's working in reverse (IIRC it should be on when the A/C is on, and off when A/C is off).

 

[cjp1280]

Thanks for the quick reply. I will check that relay tomorrow and see what I find. Hopefully I get get my high speed back, I'm gonna need that this summer.

 

[cjp1280]

I checked the relay and thats exactly what it was! Thanks. Rear blower still cuts out though. Hopefully someone can give me a clue as to whats goin on there. I'm lost on that one. Might have to take it to the dealer.$$$$$$