No power to my compressor

ssallday · Jul 3, 2015

Hey everyone I'm new to the forums here and I have a 2004 Jetta wagon 2.0. About 2 years ago my compressor was replaced with a used one and the a/c was working perfectly fine. Last year the air from the a/c began to get warmer until it completely stopped blowing any cold air. A couple of weeks ago we checked the freon lines and they had plenty of pressure in them. We also checked the fuses in the car and on top of the battery along with the fan control module. The compressor spins from the serpentine belt but the clutch does not engage and there is no power in the wires going to the compressor. There is power at the high pressure switch but the condenser fan does not come on unless the switch is jumped. Could the culprit be the ambient temperature sensor?

dennisgli · Jul 3, 2015

Condenser fan?

ssallday said:
We also checked the fuses in the car and on top of the battery along with the fan control module.

You say that you checked the Fan Control Module - so are you saying that it is supplying power to the clutch but there is no power at the clutch? Then the problem has to be the wire between the FCM and the clutch - or the ground to the clutch.

ssallday · Jul 4, 2015

dennisgli said:
Condenser fan?

You say that you checked the Fan Control Module - so are you saying that it is supplying power to the clutch but there is no power at the clutch? Then the problem has to be the wire between the FCM and the clutch - or the ground to the clutch.

I'm not sure if there is power at the control module because I picked up a used one and it would be my luck that both of them are bad. There is no power at the wire that connects to the clutch wire on top of the compressor. Today I checked the ambient temp sensor and it was good. Like you said it could be the wires but I'm not completely sure. I also checked the a/c relay and that was good. Is there an a/c wiring diagram that I could look at? Also, how would I be able to test a control module?

dennisgli · Jul 4, 2015

Condenser fan - a/c relay - where are you finding these things and how are you testing them?

There is a wiring diagram in the Bentley manual. I think there may be a DIY for checking the FCM on VWvortex somewhere. Check for power from the fuse through the FCM module to the clutch - the wires shouldn't change colors between the fuse and the FCM - and between the FCM and the clutch.

I assume that both radiator fans come on at slow speed when you turn the AC on.

ssallday · Jul 5, 2015

I found the fcm under the battery and the relay under the steering wheel. I tested the switch in the relay and it was good. The fcm I would assume is good because when ever I jump out the high press. Switch the condenser fans come on. I'm pretty sure there is power at the fcm and fuse box on top of the battery but no power at the clutch so is it most likely a wire problem between the fcm and clutch?

GRYM · Jul 5, 2015

There is a relay/solenoid under the dash for the A/C compressor too. That can be faulty. They run about 10$. There is a whole writeup to test the whole FCM system here with pic, on my tablet don't have link though.

KSW

ssallday · Jul 6, 2015

I went out today and got a relay. Unfortunately, that was not the culprit. Tomorrow I will try to mess around with the FCM but if I don't come up with anything then I have no clue what else it could be. Today I also checked the 4 pin connector on the left side of the battery leading to the wire that sits on top of the compressor and found continuity but no power.

No power to my compressor

Top Contributors this Month

Recommended Communities