Has anyone experienced this problem?

I have a 94 SC300 and while the temperature (cool/heat) can be controlled, it seems that my A/C (compressor?) is always working. When I hit the A/C button to turn off the green light, the system still sends out cold air when I crank down the temp setting on a hot day.

 

I actually seem to have a similar problem after having to replace the compressor on my 92 SC300. Curious to see if anyone knows anything about this?

 

A little more information on my problem -

The magnetic clutch is engaged all the time, even when the a/c switch is not in the on position. The magnetic clutch relay is getting battery/alternator voltage all the time as well.

Using the wiring diagrams in my shop manual, as well as the troubleshooting guide for the a/c compressor, I've come to the conclusion that my ECU is bad. Has anyone else had their ECU cause something weird in their a/c system?

 

I know it looks like I'm talking to myself, but I figured out and fixed my problem.

There was supposed to be 4-6 Volts going to wire 4 on connector A12 on the back of the climate control unit. This voltage should be sent from the ECU - I didn't have this voltage at all, so I figured my ECU was bad. I replaced it, and now everything works properly.

I have yet to open up the old ECU to see if there's obvious corrosion or capacitor leakage, but at least I can turn my a/c on and off now.

 

While it looks like you are talking to yourself, threads like this still help people who run into these problems. So describing your problem, issues and fix will help other people down the road

Jonny

 

I haven't given it much thought but my AC will run just a bit even when I turn it off. It usually goes away after a little while though.