A/C always on - even when no green light
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Has anyone experienced this problem? ![Confused](https://www.clublexus.com/forums/images/smilies/confused.gif)
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.
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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.
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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?
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?
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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.
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.
#5
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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.
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.
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Jonny
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