A/C compressor not working

Tiny
DROBLES
  • MEMBER
  • 2008 JEEP LIBERTY
Compressor will not engage have already replaced twice what can be the problem. Do not want to spend anymore money please help. Ac blowing air but compressor not engaging. What can I check before taking it to repair shop for the third time.
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Thursday, July 4th, 2013 AT 6:59 PM

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Tiny
FREEMBA
  • EXPERT
Check fuse #21 (underhood fuse box).
If it is good, swap the A/C relay with another identical relay (likely it s one in that very same fuse box).
Now turn on the a/c (engine running) to see if the compressor engages.
If not, use a voltmeter or testlight ot check for power at the a/c compressor clutch this has to be done with the engine running and the a/c on

BE VERY CAREFUL WILE WORKING ON A RUNNING ENGINE:

unplug the electrical connector at the a/c compressor clutch.

You should have 12v on the DB/YL (dark blue/Yellow stripe) wire with the engine running and a/c switch on. (Of course this is dependent upon whether or not the system has enough Freon in it to create pressure (the pressure switch has to sense pressure before it will allow the compressor to turn on). The black wire at the compressor clutch is the ground wire.

If you have 12v there and still the compressor will not turn on, suspect a faulty compressor clutch.

If you don t have 12v there, suspect that the system is low on Freon (R-134a) or that there is a open in the DB/YL wire (this is very rare).

Please post your results here for more help.
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Thursday, July 4th, 2013 AT 7:38 PM
Tiny
KEN
  • ADMIN
It sounds like you have a leak in the system which will shut down the compressor can you confirm a full charge on the system?

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

and

https://www.2carpros.com/articles/air-conditioner-leak-detection

If the charge is full we need to check the air conditioners wiring and power suplly

Here is a guide to help you

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

The air conditioner wiring diagram is below

Please let us know what you find.

Cheers, Ken
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Sunday, December 24th, 2017 AT 1:57 PM

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