AC compressor not engaging

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Jul 16, 2015 | 09:53 AM

scott79

Thread Starter

Fleet Mechanic

Joined: Sep 2009

Posts: 1,404

Likes: 14

From: Bloomington, IN

AC compressor not engaging

Hey fellas, as the temps are rising I finally turned the AC on and nothing--only hot air coming out! I popped the hood and noticed the AC compressor not engaged. After reading thru some posts, I decided it must be the low pressure switch but first I checked to make sure I had power to it---yes, checked the fuses (#1) and it was good. So, I replaced the low pressure switch and still nothing---compressor not engaging!! Also I added refrigerant just in case. Any advise for what could be my problem? Thanks

Jul 16, 2015 | 10:12 AM

farmert

Lead Driver

Joined: Mar 2006

Posts: 5,111

Likes: 1,546

From: western SD

You could jump the low pressure harness to see if you problem is on the low side, but since you added refrigerant, I doubt this is were your problem lies. Wiggle the harness behind the compressor, it may be on the high pressure side. When I got the 96 C&C, that harness was loose, and the compressor would not run.

Jul 16, 2015 | 11:23 AM

JCart

Tuned

Joined: Jan 2008

Posts: 294

Likes: 16

From: Kamloops, BC. Canada

Quote:

Originally Posted by scott79

Just to clarify when you say not engaging you mean the clutch is not triggering or the clutch is triggering (clicking and shifting into the pulley) but not gripping the pulley? If it's the later, there are iirc 1 possible 2 shims (washers) that you can remove behind the clutch (piece that shifts into and grips the pulley). To get at them just undo the Center bolt, remove clutch and shims and reinstall, without shims.

Jul 16, 2015 | 11:33 AM

scott79

Thread Starter

Fleet Mechanic

Joined: Sep 2009

Posts: 1,404

Likes: 14

From: Bloomington, IN

I mean the clutch is not engaging at all. When I turn the AC on, nothing happens, no clicking, no nothing.

Quote:

Originally Posted by JCart

Jul 16, 2015 | 04:28 PM

dclack

Fleet Mechanic

Joined: Jan 2011

Posts: 1,793

Likes: 74

From: Richland, WA

First thing to do then is to test the coil by applying 12v directly to it. If it doesn't pull the clutch in, then the coil is bad.

Jun 12, 2021 | 08:16 PM

Jwilson19

3rd Gear

Joined: Oct 2020

Posts: 3

Likes: 0

Quote:

Originally Posted by dclack

First thing to do then is to test the coil by applying 12v directly to it. If it doesn't pull the clutch in, then the coil is bad.

My A/C is doing this too. Where is the coil you are talking about?

Jun 12, 2021 | 09:57 PM

z31freakify

Hotshot

Joined: Dec 2012

Posts: 11,278

Likes: 1,658

From: Las Cruces New Mexico

Quote:

Originally Posted by Jwilson19

My A/C is doing this too. Where is the coil you are talking about?

He' talking about the AC compressor connector.

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Jun 13, 2021 | 02:05 PM

Hit Man X

Lead Driver

Joined: Sep 2002

Posts: 9,554

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From: North Texas

Quote:

Originally Posted by dclack

First thing to do then is to test the coil by applying 12v directly to it. If it doesn't pull the clutch in, then the coil is bad.

This.

Does the blower fan still work? The high switches are known to die, when that circuit is open...no power flow to the compressor. Should be a black and grey white wire I think at it. Just a couple of alligator clips are all you need, ground one pin and hit the other with battery voltage. There is also a diode up stream, but those rarely die and just allow one way voltage flow.

Your charge is now off also since you shot some refrigerant in there. How much is anyone's guess as you cannot add gas to a system that is off and pressurized in my experience.