03 AC problems maybe wiring?

[jmsprang]

I have an 03 ls V8 100k. Went to use the air this summer and noticed it was not cold. Not hot either just outside temp. I popped the hood and noticed that the compressor was not kicking on. I tested the low side to see if it was low on freon and pressure was reading good. So thinking I had a bad compressor unused a test light to see if it was getting power and there is no power going to the compressor. The 10amp fuse in the box under the hood tests good. I swapped the relay and still no power to the compressor.

I ran a datc on the control panel and it comes up 2799 and 2797. Driver coolant control valvle open circuit and Passenger coolant control valve open circuit.

Am I dealing with a wiring problem to the compressor, or A dccv valve is bad? Where is the dccv located? If the dccv valve is bad will that cut power to the compressor?

Thanks

 

[joegr]

Probably, your DCCV is failing, but that's not your issue right now.

What was the pressure reading. I'm betting that it is too low because most of your refrigerant (R134a) has leaked out. Look at the bottom of the compressor. If it's oily, that's where the leak is and you have probably lost most of your compressor oil too.

Those cheap low side gauges are not very useful for this. The LS reads high side pressure only. It has to be fairly high for the compressor to start (well above the 25 to 40 PSI that the low side should have when the compressor is running). With the compressor off, the high and low side pressures will be the same, and must be fairly high.

 

[jmsprang]

Does the compressor get the power cut to it when the system is malfunctioning? I would think it would have power all the time.

 

[joegr]

Does the compressor get the power cut to it when the system is malfunctioning? I would think it would have power all the time.

Yes, of course it does. How else could it protect itself? The compressor doesn't "get power" anyway, the clutch does. The clutch is powered when the system wants to run the compressor (and it is safe to do so), and not powered when the system is off or it is unsafe to run the compressor.

The PCM controls power to the clutch. It will turn the clutch on if:
1. The climate control tells it to. (Control is on, compressor button is on, and evaporator temperature is above freezing.)
and
2. The PCM reads the high side pressure as being high enough, but not too high.
and
3. The engine is not overheating and the engine RPM is not too low and the engine is not having any severe problems.
and
4. The driver isn't trying to accelerate above a certain amount.

Also, there is a thermal switch on the side of the compressor that will interrupt power to the clutch if the compressor is overheating.

So again, (if you really want help) what is the system pressure in PSI?