Ac compressor clutch

Rudy913

G-Body Guru
Feb 26, 2016
646
28
New Orleans
When I’m running my ac and heater
My ac compressor clutch is always spinning should it turn off when I slide it to the heater ?
I can hear a click noise when I slide it and can feel the idle difference
But the clutch is still spinning on both
My guess is that when I got the ac install
The shop didn’t do it proper
If y’all can give me any info on how I can fix it myself
 

Attachments

  • C1665712-7330-4A93-8ED0-E1DA775D9EB2.jpeg
    C1665712-7330-4A93-8ED0-E1DA775D9EB2.jpeg
    346.4 KB · Views: 50
  • F499F24E-1A8B-4971-AA87-5941E6B7E711.jpeg
    F499F24E-1A8B-4971-AA87-5941E6B7E711.jpeg
    941.1 KB · Views: 45
  • A62C24D1-7741-42AE-AB7B-D3A781FBB12B.jpeg
    A62C24D1-7741-42AE-AB7B-D3A781FBB12B.jpeg
    1.3 MB · Views: 45
  • BE8FD720-7C76-4F11-B8B0-05AAD3D85E83.jpeg
    BE8FD720-7C76-4F11-B8B0-05AAD3D85E83.jpeg
    1 MB · Views: 49
  • 28EC8191-C232-4A86-AC80-3C4EB6A78C6D.jpeg
    28EC8191-C232-4A86-AC80-3C4EB6A78C6D.jpeg
    1.1 MB · Views: 45

Rudy913

G-Body Guru
Thread starter
Feb 26, 2016
646
28
New Orleans
When I’m running my ac and heater
My ac compressor clutch is always spinning should it turn off when I slide it to the heater ?
I can hear a click noise when I slide it and can feel the idle difference
But the clutch is still spinning on both
My guess is that when I got the ac install
The shop didn’t do it proper
If y’all can give me any info on how I can fix it myself. Also I think I been having timing issues with my car running hot in the summer time I was thinking that both the ac and the heater are both putting a stain on the engine being that the clutch don’t turn off and causing it to run hot
 

350Regal

Not-quite-so-new-guy
Feb 23, 2022
42
18
On heater or on defrost cuz every vehicle that I know of runs the AC when you use the defrost even your new vehicles do
 

pagrunt

Geezer
Sep 14, 2014
8,216
113
Elderton, Pa
On heater or on defrost cuz every vehicle that I know of runs the AC when you use the defrost even your new vehicles do
On my '14 Silverado it uses the outside temp to kick on the compressor when not in direct A/C mode. Seems like it has to be somewhere in the mid 50's outside for it to kick on.
 

Ribbedroof

Comic Book Super Hero
Supporting Member
Jan 4, 2009
4,533
113
Wellston, OK
Are you sure the clutch plate is actually pulled in? Obviously, the belt drive will be going all the time, but the forward plate should only pe pulled in and actually turning the compressor shaft when in A/C or defrost.

If they connected the green wire to a "hot in run"/"ignition on" terminal, the clutch would be engaged all the time. It should be connected to the cycling/pressure switch on the accumulator
 
  • Like
Reactions: 1 user

Rudy913

G-Body Guru
Thread starter
Feb 26, 2016
646
28
New Orleans
Are you sure the clutch plate is actually pulled in? Obviously, the belt drive will be going all the time, but the forward plate should only pe pulled in and actually turning the compressor shaft when in A/C or defrost.

If they connected the green wire to a "hot in run"/"ignition on" terminal, the clutch would be engaged all the time. It should be connected to the cycling/pressure switch on the accumulator
Yea the plate is on all the time even when heater is on . So I gotta run the wire to the cycling pressure switch instead your saying. I’m going to take more pics of how they have the wires ran . Hopefully that can show y’all more of what I’m dealing with and be an easy fix And hopefully I don’t screw anything up
 
  • Like
Reactions: 1 user

Rudy913

G-Body Guru
Thread starter
Feb 26, 2016
646
28
New Orleans
Are you sure the clutch plate is actually pulled in? Obviously, the belt drive will be going all the time, but the forward plate should only pe pulled in and actually turning the compressor shaft when in A/C or defrost.

If they connected the green wire to a "hot in run"/"ignition on" terminal, the clutch would be engaged all the time. It should be connected to the cycling/pressure switch on the accumulator
Can I upload videos on here? I’m curious
 

oldsmobile joe

Royal Smart Person
Nov 12, 2015
2,044
113
mpls
Don't confuse heat with ac operation. Your compressor is designed to turn on when the mode selector in placed in "max", "bi-level", and "defrost" position. Ac compressor operation should not happen in "vent" or "floor" position.

The temperature position only affects the length of time the compressor runs (cycles).
 
  • Like
Reactions: 1 user

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,012
113
Does the compressor EVER cycle on and off?

Your compressor should only engage in 4 positions:

Max
Norm
Bi-Level
Defrost (running the compressor in this mode decreases relative humidity in the air so you're not just pumping moist air on a cold windshield, which obviously isn't a great idea)

And then only engage when there's sufficient refrigerant charge in the system. Generally, the cycling switch on the accumulator is what controls the system pressure by cycling the compressor. Typically on at ~48 psi, off at ~25 psi. This protects the system from freezeup. Most of these switches can be range adjusted slightly, depending on manufacturer of the switch. There could be other control systems that temporarily cut out the compressor in certain conditions, such as full throttle cut out, high effort power steering, temperature/pressure cutouts, etc. Not familiar with Monte Carlo sub-systems that well.

When on MAX, the temperature control is basically useless as the coolant cutoff valve is controlled by the main vacuum system. Otherwise, the two-port valve lines up to apply vacuum when the temp control lever is in full cold position only. Anything off full cold will release vacuum to the coolant cutoff valve except when in MAX.


Below is compressor wiring for 1985 Oldsmobile. Your Monte should be SIMILAR, but may be different in places as well. Again, not familiar with the Monte setups. If anyone has a wiring diagram that can help drill down, be my guest. Note the positions of the mode selector switch on the first picture. This is when your compressor should be free to engage.

85-csm-ac-compressor-wiring-1-jpg.115262


VIN Y, 9, and A.
85-csm-ac-compressor-wiring-2-jpg.115264


You can see the switch on the back side of this accumulator with the black wiring plug going to it (switch itself is silver aluminum ring and white plastic here):
20190401_212747_resized-jpg.119605
 
Last edited by a moderator:
  • Like
Reactions: 1 user

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact Admin@GBodyForum.com for info on becoming a sponsor