When I set A/C-Heat selector to "Max", "Norm", or "Bi-Level", the AC compressor kicks in, the idle solenoid increases the idle speed and the radiator fan comes on. However, when I set it to "Defrost" only the AC compressor kicks in. The idle speed does not increase and the radiator fan does not come on. Is that normal, or do I have a problem with the selector switch?

 

thats how its supposed to be

 

OK, Thank you very much.

 

I'm almost certain the idle bump solenoid and the fan should come on in defrost. I know the bump solenoid does for my 85. It's been too infrequent driving my 87 for me to recall. I could check...

A wiring diagram would show the intended function but some are not to be trusted.

 

I noticed it in October when I put it on defrost to clear inside windshield fog. At idle, the compressor started groaning and the temperature gauge shot up. I opened the hood and saw that the radiator fan was not on. I switched to A/C Norm and the idle increased, getting rid of the groan and the fan came on and cooled down the engine. I think you're right and I have a problem with the control switch. I will check my Haynes & Chilton wiring diagrams to be sure. Then I will pull out the control assembly and see what I have. Thanks so much for your time.