99 GMC Yukon a/c

[Jrod85]

Hello everyone I hope someone can help me. I have a 99 GMC Yukon 5.7. I just bought the truck and am having trouble with a/c. The a/c compressor only kicks on when blower switch is on off as soon as I turn it to low or high the compressor shuts off. I don't understand what's going on. It is very hot in fl and can't have my son burning up every time we need to go somewhere. Please help!!!!!

 

[SunlitComet]

blower switch is supposed to have opposite effect on the compressor control so replace that

 

[Jrod85]

blower switch is supposed to have opposite effect on the compressor control so replace that

I replaced the switch andand it still does the same. While moving wires around I noticed that the light on a/c button would come on and off now I have to figure out what is causing that. Thank you for your help I have a start on it now.

 

[Jrod85]

Ok I was going through the blower control switch wires and a light blue and a brown one were messed with right on the plug in. I have no idea what's next. Please help!!!!!

 

[OR VietVet]

I have no idea what "messed with" means.

 

[SunlitComet]

I can help you but please rephrase.