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2003 Jeep Liberty Sport 3.7L Compressor Issue

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willifordb
New User

May 26, 2012, 1:46 PM

Post #1 of 5 (7940 views)
2003 Jeep Liberty Sport 3.7L Compressor Issue Sign In
Year of vehicle: 2003
Make of vehicle: Jeep
Model of vehicle: Liberty Sport 4X4
Engine size: 3.7L
Mileage: 114000
Compressor clutch is not engaging. Checked fuse to a/c clutch under the hood- it's good. changed A/C clutch relay with O2 relay (same exact relay p/n) and seems to be good. I disconnected the cycling switch connector from the accumulator and connected a jumper on the harness side to see if it was this switch. compressor clutch still didn't engage.
Don't have my multi-meter with me to check signal at compressor clutch connection.

Just trouble shooting to see what is wrong before paying for work.
Any help would be appreciated on possible issues or further trouble shooting steps.

thanks


(This post was edited by willifordb on May 26, 2012, 1:50 PM)


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

May 26, 2012, 2:17 PM

Post #2 of 5 (7921 views)
Re: 2003 Jeep Liberty Sport 3.7L Compressor Issue Sign In
Your going to have to take it to a shop.

The first thing that they will do is make sure that there is some type of charge in the system from the static pressure readings.

Then they will scan for trouble codes in the module(s) concerning the AC system to be sure there aren't codes in there inhibiting ac clutch engagement.

Next they will monitor the switch signals from the low cut off switch and ac request input. They will also monitor the ac pressure transducer voltage and see if the PCM is commanding the ac relay. All this done with an enhanced scan tool.

That will give them a direction to look for the problem.

Don't override the clutch if you are not monitoring the high and low side pressure readings or else you'll cause expensive system damage. Don't jump the ac pressure transducer supply voltage to ground unless you want to fry the PCM.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on May 26, 2012, 2:21 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 26, 2012, 3:36 PM

Post #3 of 5 (7899 views)
Re: 2003 Jeep Liberty Sport 3.7L Compressor Issue Sign In
willifordb: No problem to get this diagnosed and an estimate before any work done. Could be relatively simple or nasty expensive. A/C can have either simple or complex and expensive problems. You could see with a plain test light is power is getting to a LPCO (low pressure cut out) switch and if so then could be relatively simple to see if that power passes thru that switch but if you did jumper wire it and there was power it should have gone on to engage clutch which may just have a gap too large to engage or more problems.

You can check that gap yourself without tools. Standard biz card if folded should barely fit it that gap. If so loose it falls out could be just a job to adjust the compressor's clutch gap or who knows. Don't go jumping just anything as DS said or risk causing a problem that you may not have now!

T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 26, 2012, 3:57 PM

Post #4 of 5 (7892 views)
Re: 2003 Jeep Liberty Sport 3.7L Compressor Issue Sign In
Quote
You could see with a plain test light is power is getting to a LPCO (low pressure cut out) switch and if so then could be relatively simple to see if that power passes thru that switch but if you did jumper wire it and there was power it should have gone on to engage clutch which may just have a gap too large to engage or more problems.
Tom, you have been away too long. Those simple circuits are a thing of the past. This one has a 3 wire switch that sends actual pressures to the PCM and it uses logic to control the compressor relay.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 26, 2012, 4:15 PM

Post #5 of 5 (7874 views)
Re: 2003 Jeep Liberty Sport 3.7L Compressor Issue Sign In
Should have said not to jump THREE WIRE switches at a great risk of blowing something if there ever was power there. LED test lights are far less apt to cause a problem just to test for power. Two wire switches of course (LPCO) are just on off switches as we know,

T






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