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Old 01-28-2010, 12:07 AM   #1
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Default A/C compressor cycling.

Hey all!
I just charged my AC system today. I did a good hour evacuaction and Vaccumn to remove all moisture and old refrigerant. I then put HFC 134a in the system. Started the car up, and if I manually turn the AC compressor on, the low side lines get cold, and cool air comes out of the vents. The compressor will not come on on its own.

I checked the relay, both pink wires hot at all times. The wire that the pcm is supposed to ground to energize the relay is not grounding. The other wire energizes the compressor clutch.

I then checked the low side pressure cycling switch, along with the high side cycling switch, and both are supposed to signal the PCM that the sensors are closed, and to turn on the AC compressor. I'm getting the ground, but the green wire that comes from the AC request does not have voltage.

I did have a whack of HVAC codes. 2 which were communication errors between the HVAC and PCM. another low freon code, and one code 34 which I could not find any info on. I cleared them, and rechecked for codes and only got 34. I did not drive the car, but I did start it.

So, where should I look next?
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Old 01-28-2010, 08:09 AM   #2
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?? How do you manually turn the A/C on?

So did you do the paper clip test on the high side and the low side to fool the system and verify compressor turn on?
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