New Compressor Installed-Clutch not turning on-whats wrong? - Page 3 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat

Everything Electrical & Electronic Have an electrical problem? Lighting, Alternators, gauges, DIC, HUD, etc? Post it here. Please post Audio problems in the Audio forum, and Engine control problems in the appropriate Mechanical forum for your year.

Thread Tools Search this Thread
Old 08-14-2006, 07:05 PM   #21
Junior Member
Join Date: May 2006
Location: BonnevilleHell
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
clm2112 is on a distinguished road
Default Re: New Compressor Installed-Clutch not turning on-whats wro

Just checking back in to see how it'* going.

I did find a wiring diagram for a '93. It'* a bit different than my 90.

First, I have three pressure switches, yours only has two. (Cycling switch on the accumulator and High Pressure Cutout on the back of the compressor)

2nd, My ECM only gets feedback from the switches to know when the compressor is running and kicks high idle. Yours has a PCM that reads the pressure switches on one circuit, then commands the clutch on a seperate circuit. That explains why your wires are going into the dash.

So, in a nutshell, the switches tell your PCM that conditions are right to turn on the AC compressor. Then the PCM activates the relay that is connected to the clutch.

Also, according to the wiring diagram, you have another fuse in the "Relay Center" that is only used to run the AC clutch and it'* relay.

Those two pink wires in the relay socket are actually on the same circuit and lead back to that 15Amp fuse. And you should be able to test +12VDC on them whenever the ignition is in the run position.

The Dark Green wire comming out of the relay socket is supposed to go straight to the compressor clutch (and also to a diode). Put +12VDC to that wire and the clutch should come on.

The Light green wire (or Drk Green with White Stripe) is going to the PCM. That'* the wire the PCM grounds out to activate the relay.

On the switches, You got a light green wire comming through the firewall from the heater/AC control unit (***** and dash switches) that leads to the High Pressure Cutout switch on the compressor. The blue wire from that switch goes back to the Cycle switch on the Accumulator. The other post on that switch (also shown as a dark blue wire in the diagram) leads back through the firewall to the PCM,
clm2112 is offline   Reply With Quote
Old 08-15-2006, 12:20 AM   #22
Senior Member
Posts like a 4 Banger
Thread Starter
Join Date: Mar 2006
Location: Maryland
Posts: 112
Thanks: 0
Thanked 0 Times in 0 Posts
IKZ is on a distinguished road

Wow Curt...thank you for the info. I should have my hands on a multi-meter tomorrow, and hopefully be able to trace out where this problem is coming from.

I certainly couldn't have done this without your help, and I want you to know I appreciate it. I chime in again tomorrow night and let you know how this pan out. With any luck, by the end of this week i'll have a frigid AC system in my car. Thanks again Curt.

IKZ is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
A/C Compressor Clutch not engaging NarousPK Pontiac 16 07-04-2011 01:23 PM
A/C Compressor Clutch not Engaging Muslimsteel 1992-1999 5 04-27-2005 11:10 PM
Trying to replace ac compressor and clutch harley 1992-1999 6 09-09-2004 07:03 PM
A/C compressor Clutch is comming apart Hojekang 1992-1999 7 10-09-2003 06:34 PM
AC compressor clutch not engaging theJMFC 1987-1991 10 07-28-2003 01:38 AM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 04:40 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.