View Full Version : A/C clutch not engaging
Trolatron
16th March 2025, 07:21 PM
Hi Patrolers,
2009 crd wagon.
Aircon clutch is not engaging so l am trying to energize the magnet to check it. l ran a wire straight from the battery to the single wire on the a/c pump and got sparks. Put test light on it and fond it to be negative. The body of the pump is ment to be negative and the single wire should be a positive feed. What's happening and how do I test the magnet. Are there other sensors that stop the magnet engaging like the pressure switch, low gas or something else?
Fuse and relay seem to be okay.
mudnut
17th March 2025, 12:15 AM
After scrolling through the workshop manual, depending on your setup it could be a few things like a loose connector, faulty Engine Control Module or faulty relays. With the drive belt loose and If you have power to the magnet then you should feel resistance when you try to spin the pumps pulley. The pulley should spin freely when the power is off.
PeeBee
17th March 2025, 09:04 AM
Hi Patrolers,
2009 crd wagon.
Aircon clutch is not engaging so l am trying to energize the magnet to check it. l ran a wire straight from the battery to the single wire on the a/c pump and got sparks. Put test light on it and fond it to be negative. The body of the pump is meant to be negative and the single wire should be a positive feed. What's happening and how do I test the magnet. Are there other sensors that stop the magnet engaging like the pressure switch, low gas or something else?
Fuse and relay seem to be okay.
This is a very odd fault, reverse polarity all by itself??? Have you been doing any wiring or switch work under the dash, had the a/c switch disconnected and then re-connected? Have you tried the operation of the clutch with the a/c switch in the off position? I went thru a problem and it was my error, had connected the wires in reverse to the a/c switch and it was off when it showed on etc.
Power is + to the wire off the clutch and if the switch is on, it will spark on contact with the 12v external feed, but then it should engage also. You should be able to do this with the ignition switch in the on position, blower will indicate if you have the power. Apart from that your assumptions are correct I think
Brissieboy
17th March 2025, 09:39 AM
The terminal on the clutch will test as negative because it has a low resistance coil connected to ground/negative. A small spark would be expected when connected to battery positive, and that connection should engage the clutch with a fairly obvious click. If it sparks badly and/or the clutch does not engage when the direct connection is made then it looks like the clutch if faulty. If the clutch does engage then start looking at things like fuses, relay, the interlock with the fan switch etc.
mudski
17th March 2025, 10:29 AM
Low gas will stop the compressor from engaging. It did in mine...
Trolatron
17th March 2025, 04:54 PM
The only thing l have changed was the blower fan resistor as speed 1,2 and 3 stopped working. Might have to take it and get the gas cheeked like Mudski said.
Trolatron
17th March 2025, 04:58 PM
The terminal on the clutch will test as negative because it has a low resistance coil connected to ground/negative. A small spark would be expected when connected to battery positive, and that connection should engage the clutch with a fairly obvious click. If it sparks badly and/or the clutch does not engage when the direct connection is made then it looks like the clutch if faulty. If the clutch does engage then start looking at things like fuses, relay, the interlock with the fan switch etc.
Thanks, I will check it again.
Powered by vBulletin® Version 4.2.2 Copyright © 2025 vBulletin Solutions, Inc. All rights reserved.