Notices
1994.5 - 1997 7.3L Power Stroke Diesel  

AC compressor not engaging

Thread Tools
 
Search this Thread
 
Old Jul 16, 2015 | 09:53 AM
  #1  
scott79's Avatar
scott79
Thread Starter
|
Fleet Mechanic
15 Year Member
Liked
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
 
Reply
Old Jul 16, 2015 | 10:12 AM
  #2  
farmert's Avatar
farmert
Lead Driver
20 Year Member
Liked
Loved
Community Favorite
Joined: Mar 2006
Posts: 5,098
Likes: 1,504
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.
 
Reply
Old Jul 16, 2015 | 11:23 AM
  #3  
JCart's Avatar
JCart
Tuned
Joined: Jan 2008
Posts: 294
Likes: 16
From: Kamloops, BC. Canada
Originally Posted by scott79
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
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.
 
Reply
Old Jul 16, 2015 | 11:33 AM
  #4  
scott79's Avatar
scott79
Thread Starter
|
Fleet Mechanic
15 Year Member
Liked
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.

Originally Posted by JCart
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.
 
Reply
Old Jul 16, 2015 | 04:28 PM
  #5  
dclack's Avatar
dclack
Fleet Mechanic
15 Year Member
Liked
Joined: Jan 2011
Posts: 1,792
Likes: 72
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.
 
Reply
Old Jun 12, 2021 | 08:16 PM
  #6  
Jwilson19's Avatar
Jwilson19
3rd Gear
Joined: Oct 2020
Posts: 3
Likes: 0
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?
 
Reply
Old Jun 12, 2021 | 09:57 PM
  #7  
z31freakify's Avatar
z31freakify
Hotshot
10 Year Member
Liked
Loved
Community Favorite
Joined: Dec 2012
Posts: 11,267
Likes: 1,649
From: Las Cruces New Mexico
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.
 
Reply
Old Jun 13, 2021 | 02:05 PM
  #8  
Hit Man X's Avatar
Hit Man X
Lead Driver
20 Year Member
Liked
Loved
Community Favorite
Joined: Sep 2002
Posts: 9,497
Likes: 2,020
From: North Texas
Thumbs up

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.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-1

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-2

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-3

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-4

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
story-5

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

 Brett Foote
story-6

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

 Michael S. Palmer
story-7

10 Most Surprising 2026 Ford Truck Features!

 Joe Kucinski
story-8

Top 10 Ford Trucks Coming to Mecum Indy 2026

 Brett Foote
story-9

5 Best / 5 Worst Ford Truck Wheels of All Time

 Joe Kucinski
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mahause
1997 - 2006 Expedition & Navigator
40
Nov 22, 2013 06:53 PM
pecanflyboy
Cooling, Heating, Ventilation & A/C
6
Nov 5, 2012 12:33 PM
michaelbrainardatwor
Cooling, Heating, Ventilation & A/C
4
Dec 9, 2007 08:01 AM
cobramustangboy
Cooling, Heating, Ventilation & A/C
9
Jul 3, 2007 12:43 AM
wardenj
1978 - 1996 Big Bronco
6
Aug 11, 2002 11:10 PM




All times are GMT -5. The time now is 09:17 PM.

story-0
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-1
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-2
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-3
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-4
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-5
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-6
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE
story-7
10 Most Surprising 2026 Ford Truck Features!

Slideshow: 10 most surprising Ford truck options/features in 2026.

By Joe Kucinski | 2026-05-05 11:17:22


VIEW MORE
story-8
Top 10 Ford Trucks Coming to Mecum Indy 2026

Slideshow: Here are the top 10 Fords coming to Mecum Indy 2026.

By Brett Foote | 2026-05-04 13:49:49


VIEW MORE
story-9
5 Best / 5 Worst Ford Truck Wheels of All Time

Slideshow: The 5 best and 5 worst Ford truck wheels of all time

By Joe Kucinski | 2026-04-29 16:49:01


VIEW MORE