No power to ac compressor
Thread Starter
|
Fleet Mechanic
Joined: Oct 2008
Posts: 1,321
Likes: 250
From: North Texas
No power to ac compressor
I lost AC the other day mid-route driving in my F350 - just blows warm air. Took it to a shop to have the system fully evacuated and recharged. No leaks detected but the compressor still is not kicking on. There's no power to the binary high pressure switch behind the compressor. No luck wiggling the wires or connector. The 10a fuse in the cab for the compressor clutch tests good. Before I go disrupting wire insulation to see if there's power before the plug, is there a relay I'm missing in the owners manual here?
It's a Van Gogh
Joined: Feb 2010
Posts: 7,813
Likes: 1,335
From: Elk Grove, CA
I'll attach the 2000 F250 Owner Manual. I did not see an AC Relay, just a fuse, but definitely check I may have missed it.
So the AC clutch does not engage at all? You can take some leads and jump 12v to the clutch and see if it moves. If it doesn't engage the clutch coil is bad. Just went thru this with my daughters Jeep Liberty, clutch engaged when jumped but no joy when running. I think there were 3 fuses and 2 relays involced.
Turned out to be the low side pressure switch.
Here's also a good video on adjusting the air gap.
So the AC clutch does not engage at all? You can take some leads and jump 12v to the clutch and see if it moves. If it doesn't engage the clutch coil is bad. Just went thru this with my daughters Jeep Liberty, clutch engaged when jumped but no joy when running. I think there were 3 fuses and 2 relays involced.
Turned out to be the low side pressure switch.Here's also a good video on adjusting the air gap.
Thread Starter
|
Fleet Mechanic
Joined: Oct 2008
Posts: 1,321
Likes: 250
From: North Texas
Thanks. I'll try the jumper wire. I figured it wasn't an issue with the air gap since there's a lack of power unless I'm mistaken that the air gap would be a mechanical issue only, not electrical.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
Is there power at the switch on the accumulator? If no the there is a main connector up in the corner where the inner fender meets the firewall. The A/C is on it's own little mini harness starting w/ that connector. If no power there then could be dealing with a in cab controls issue. If you do have power to the other switch then the wiring problem should be between the switch and the inner fender.
Mountain Pass
Joined: May 2006
Posts: 194
Likes: 31
From: Summerfield
Wiggle the high pressure switch/wiring pigtail next to A/C compressor while the A/C is on. Over time these(switch/wiring plug) tend to lose the ability to make a good connection, especially if they have been leaned on while doing other work on the engine. I had the same issue. Hope this helps
Thread Starter
|
Fleet Mechanic
Joined: Oct 2008
Posts: 1,321
Likes: 250
From: North Texas
Is there power at the switch on the accumulator? If no the there is a main connector up in the corner where the inner fender meets the firewall. The A/C is on it's own little mini harness starting w/ that connector. If no power there then could be dealing with a in cab controls issue. If you do have power to the other switch then the wiring problem should be between the switch and the inner fender.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,352
Likes: 5,946
From: Lake Hartwell, GA
Trending Topics
Thread Starter
|
Fleet Mechanic
Joined: Oct 2008
Posts: 1,321
Likes: 250
From: North Texas
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Thread Starter
|
Fleet Mechanic
Joined: Oct 2008
Posts: 1,321
Likes: 250
From: North Texas
I dug into this further today. The sensor on the accumulator is presumably bad as jumping the plug causes the compressor to kick on. Is this sensor valved to where I can I pull to replace without evacuating the system again?
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
Yeah, I'm on my third high pressure switch now. The pins are carrying more current than is wise to design in there and they just burn up. New switch and plug kit and I'm good for a while.
Thread
Thread Starter
Forum
Replies
Last Post
TheKirbyMan
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
7
Sep 18, 2010 10:01 PM
Buggie
Cooling, Heating, Ventilation & A/C
4
Sep 25, 2004 07:52 PM
cbird
Explorer, Sport Trac, Mountaineer & Aviator
2
Mar 20, 2004 01:17 PM