Question about 1996 GMC Sierra

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I did charge the a/c. I bypass the system by the fuse box, removing the relay and placing a jump wire to run the compressor while recharging. Then when I am done, I replaced the relay and start the engine and turn on the dash board a/c button. THE A/C DID NOT WORK, the blower was turning but no cold air and the compressor clutch don't engage.

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Probably the high pressure switch on the accumulator - try disconnecting the connector and jumping the pins to see if the clutch will engage. If that is the problem, DO NOT leave it jumped - replace the switch.
If that is not the problem, you will have to check the clutch wiring, relay and fuse for continuity back to the HVAC controls. If that is OK, the problem will probably be in your HVAC control module.

Posted on Oct 16, 2017


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Posted on Jan 02, 2017



  • 85223 Answers

SOURCE: A/C Cluth not working-replaced Cycling Switch already

The Low pressure switch and the compressor cycling switch are one in the same.

Posted on Apr 22, 2009


frank thomas wilson

  • 10319 Answers

SOURCE: 99 Suburban A/C Not working

The A/C pressue switch may be bad as well. Also the mode switch on the control head inside the vehicle. There are many other exsisting problems pertaining to a/c. I suggest a manual from Auto Zone for many faults can be noted especially wiring can be at fault

Posted on May 23, 2009


Ronny Bennett Sr.

  • 6927 Answers

SOURCE: Fuse is OK but air conditioner doesn't work '94 GMC Yukon.

yes alow presure switch is likely on GM and it could be out of freon ,safe way to tell is to put a set of gauges on it and it will tell by passing the low side switch will just destroy the compressor if it is out of freon

Posted on Jun 28, 2009


Donnie Wilson

  • 986 Answers

SOURCE: 1998 GMC C3500. The

your low on freon.

Posted on Sep 05, 2010

Ted Schore

  • 7353 Answers

SOURCE: brake light not work. done all checking blubs is

the brake light switch powers the wire which goes to the turn signal switch. So I think if the turn signals works, then the turn signal switch is bad. Check for power at the wire going from the brake switch to the turn signal switch. . Since you didnt tell what year or model the truck is, I cant tell you what the wire color is.

Posted on Dec 10, 2010

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96 twn & cntry 3.8, A/c quit. Fuse & relay good. jumper wire at relay, comp engaged. Cold air! Charge shows good with recharge hose from Auto Zone. A/c switch not turn system on.

Check the switch for continuity. It should be signaling the pcm to turn on the compressor. Also check the low pressure switch connector. You might try bypassing the low pressure switch with a paper clip in the connector. If that works, you could just leave it bypassed or replace it. Check the continuity of all three wires to the pcm. They can be seen in the upper half of the diagram below on pins 38, 42, and 64 of the pcm connector.


Aug 17, 2017 | Cars & Trucks

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Where is the compressor cluth relay located on a 2005 Pontiac grand prix? I know of one in fuse box as well as a 10amp fuse. Both are believed to be good. Brand new a/c compressor and clutch. Clutch won't...

You say you believe the relay is good. Just a thought, I have had a couple cars where the same relay was used for several things. If you have the same relay for something else maybe you can swap them to see if it works. I did this by putting the A/C relay in place of the fuel pump relay and found the fuel pump relay was bad. If you do this and the car will not run long you know the relay is bad.

Jul 30, 2017 | Pontiac Cars & Trucks

1 Answer

AC compressor clutch wont engage

Compressor will not run if freon charge low. If you want it to run supply direct power and ground to back of compressor. I do not recommend a home recharge as you will not be able to evacuate the moisture in the system and inject adequate amounts of oil

Apr 12, 2015 | 2007 Chrysler Town & Country LX New Cars

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2004 suzuki aerio 2.3 a/c compressor not engaging power to it.fuses and relays are good good freon

Could be the clutch,, try bypassing and jumping dierectly to compressor.. if it runs its in your wiring.. if it does not run.. its the clutch.. Look for part at

Aug 20, 2014 | Cars & Trucks

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2001 Oldsmobile Alero 4 cyl , Air Conditioning, compressor clutch will diss-engage. Blower fan is working, Freon psi is good, All the fuses and relays are good, Did some testing, and the compressor and...

The pressure means nothing as far as the state of charge. You need to have the system completely evacuated and recharged with the specific charge weight for that vehicle. Only then can the pressures or anything else mean anything.

Aug 18, 2013 | 2001 Oldsmobile Alero

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Is the switch that turns on cooling fans the same switch that turns on the air compressor i just replaced compressor and other parts and had it vacumed out ,oiled and recharged . and compressor wont

possible you have a bad low or high pressure switch on a/c system bad causing compressor not to engage, find switchs and jump across wires and see if compressor engages

Sep 03, 2012 | Kia Cars & Trucks

1 Answer

A/C Compressor wont kick on unless jumped in fuse box using a paper clip. Compressor does not kick on with relay in place. Freon levels are between 35-40psi on low and 190-200psi on high side.

Normal pressure with the engine-compressor off is outside air temp. So both gauges would read 70 or 80 or whatever.
When the system is running, normal is 30-50 low and 200-300 high.
One thing that comes to mind to test is the low pressure switch.

Jul 14, 2012 | 2001 Chevrolet Malibu

2 Answers

A/c compressor clutch will not engage

In this case, I would suggest that the low freon pressure switch has activated and prevents the compressor from running and damaging your system in your 15 year old vehicle. To prove this, find the switch and short the switch out and see if the compressor kicks on.

How do you fix this? Get the system recharged. Also have the mechanic check for leaks. The freon escapes somehow ...

Thanks for your question today.

Mar 03, 2011 | 1996 Cadillac DeVille

1 Answer

How do you remove the air conditioning pressure switch? we are trying to charge the a/c but need to keep the compressor running and can't figure out how to remove this switch to "jump" it.


I always jump the relayi instead of the sensor, it is easier and don't run the chance to screw up the sensor.

Look for the fuse box in the engine compartment, usually by the battery, take the cover off and look inside, there is a diagram with the location of the fuses and relays, look for the A/C Clutch Relay, (it may not say Clutch in it), look at the diagram in the relay to see which terminals are for the load and which are the ones to activate the coil, turn the key in the Ignition to the "Run" positiion, insert a piece of wire in the holes between the load terminals(usually are 86 and 30), no need to insert relay back, you should hear a click coming from the compressor clutch been activated. Remove Jumper and replace Relay when done working on A/C compressor;

Don't forget to rate this post. Good Luck!!!

May 24, 2010 | 2004 Honda Accord

2 Answers

Can't get clutch to engage on air contioner.

Best bet is to recharge the system, and check your fuse blocks. You can purchase a recharge kit for approx. $30. Ensure that your fuses are good, and check the wiring for a short.

Jun 01, 2009 | 1992 GMC Sierra

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