I have a 2015 Rubicon Unlimited with only 22,000'. The AC suddenly stopped working. The compressor can be turned by hand (definitely not seized), but the clutch is not engaging. Plenty of R22 in the system so it is not a low pressure issue. To confuse the situation, I pulled the connector to the clutch and it measures 14v whether or not the AC switch inside is On or Off. This doesn't make sense to me and was wondering if anyone had suggestions for troubleshooting the electrical side and why I'd be measuring voltage at the clutch with the switch in the OFF position.

 

Defrost will run the A/C too, suggest checking the resistance of the clutch coil windings. Don't know what it is supposed to be, but if it's near infinity it's bad

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Thanks - I will check the coil resistance today. I did try defrost as well without any difference.

 

A/C clutch coil resistance readings at 70°F are as follows:

Compressor Zexel DKS-17DS is 4.0 - 4.4 ohms, 3.3 amps max draw
Compressor Visteon RS-18 is 3.0 - 4.0 ohms, 4.0 amps max draw

 

Thanks all. Check of mine and resistance is infinite. Definitely looks like an open coil, but still not sure why the lead voltage was present with the AC / defrost off... Anyway, I'll replace the clutch and let everyone know what happens.

 

What was the result?

 

You're on the right track. The PCM switches the neutral ground side of the clutch to ground and then it pulls in. As you say the clutch will have around 14v all the time.

Let us now how you get on.

 

That phrasing reads like someone with AC electrical experience ...

 

With the 2008 and 2012 JKs, the AC clutch coil is connected to ground, and the PCM sends a signal to the TIPM, which sends 12v to the clutch coil.
My 2008 AC clutch coil gets 12v only when AC and/or Defrost is selected. Are the later JKs different?

If the OP was getting 12v to the coil connector all the time, maybe that was part of the issue.
It would have been nice if he had updated this thread.