My 91 camry with 4 cylinder engine has a/c problems . The a/c blows nice and cold no problems , Fans are running just like they are supposed to , the problem is if I hit the button on the dash with the green light on it to turn off the a/c compressor it does not turn it off . The light does go off but the compressor still runs and cycles as if the button was on . If I turn off the blower switch the compressor does shut off as it should . I would think the push button switch is working due to the fact the light goes off , but what else could it be ? I will test the switch this weekend to be sure it is working . Anyone have any other ideas ?

Compressor clutch relay stuck?

It won't be the clutch relay if he can turn it off with the blower motor. The blower fan switch in the off position will cut power to the A/C amplifier module and turn off the A/C.

If you look at the A/C schematic in the A/C manual section p4: http://www.camrymanuals.com/index.php?m=Home&cid=105&topicid=0, it looks like there are 3 wires which come off the A/C switch. One is from the blower/heater relay, one goes back to the A/C amplifier, and the other provides switched power to the indicator light whose other end goes back to the A/C amplifier as well. Depending upon the design of the A/C switch, if it is a dual pole design, then it could still work for the A/C light indicator but stick for the pwr switching into the the A/C amplifier module. To test that theory, you can yank out the connector at the back of that A/C switch. If it turns off the compressor, then the switch has to be bad. If it doesn't, then the A/C amplifier must be bad.

dave mc

Right - I misread his description