Grandson has replaced a/c control 3 times on his '97 full size. KO's the control each time. All fuses good, all grounds good (measured) All blower speeds good. Temp actuator works. Has no recirc.,a/c compressor, no upper/lower mode control. Have posted this prob. in other forums >no help. Cant get any info from Chevrolet dealers. I have read others have had this prob. Anyone on the planet heard of this? I know theres a fix but I cant find it.

 

I personally have never run into this problem. However there is a web site that my work is subscribed to called International Automotive Technicians Network, it is where techs post strange or difficult problems. I just looked on the site and found several posts of this problem with many things to check. Unfortunately there is to many to post here. If you want to look at them yourself you could sign up. The name of the site is IATN.com

 

Well into the same prob with my c2500 and even tho there is a age dif between our trucks i would take out the glove box and look for a large red wire that runs over to the driver side as well as out to the firewall, on mine we couldnt figure out what was wrong till i was tracing wires and that one was shorting out and melting at a plug, so we cut the red wire and by-passed the connector and now it works like a champ.

 

Thanks for your suggestions. I believe I have found the prob thru "Idendifix' web site. Valuable stuff there! Any serious tech should look into it. In the example I stated, turns out to be the pressure cut-off switch and wiring at the compressor(rear).