AC problems
Freshman User
Joined: Aug 2012
Posts: 46
Likes: 0
From: Washington State
My A/C was blowing warm air so I purchased a can of A/C PRO at a local parts store a couple weeks ago. My system was so low the compressor would not come on. I put a 20oz can in and the compressor started working. I let the truck idle for the recommended fifteen minutes and the air was not so cold anymore and the gauge was reading low. So, off I went to the parts store to buy another can. It is in the correct range on the gauge now. I was wondering how accurate the gauge was on this can so I had a friend hook up his professional A/C gauges and it was reading the same as the one on the can. I took the truck for an hour drive last weekend with the family to a lake for a picnic and noticed the A/C started blowing a bit warmer air, so I shut it off and rolled down the windows. I have noticed after all this my compressor does not cycle off and on, it just stays on even when the ambient temp is 65 degrees. I checked the pressure yesterday and it is holding in the correct range still. I am wondering about the air gap so I will get some feeler gauges and check to see if I am in spec. I stumbled onto this site and love it! I will post my findings when I get them. Thanks everyone for the great info!
Freshman User
Joined: Aug 2012
Posts: 46
Likes: 0
From: Washington State
I borrowed my neighbor’s feeler gauges today and checked my air gap. It was about .037" so I removed the clutch per directions and removed the only shim. Put it back together and it is .021" ran the truck and the clutch did not turn until I turned on the A/C, then it engaged. Hooked up my low pressure gauge and checked the pressure and it read 24 psi with the fan on low. The ambient temperature at this point is 70 degrees. I put a meat thermometer in the vent closest to the steering wheel and after just a couple minutes, it was reading 40 degrees. I turned the fan on high and noticed the pressure went to 35 psi and the temperature in the vent started to rise. I turned the fan back down to low and the pressure dropped back to 24 psi and the temperature went back down to 40 degrees. I noticed the clutch still is not cycling it just stays running. I left the gauge hooked up to see what the pressure was off and it read about 94 to 95 psi. Any ideas on what to do next? 
Thank you, Danny W.
Thank you, Danny W.
Senior User
Joined: Sep 2004
Posts: 121
Likes: 0
Bump. Haha. Wife just described the same thing as most. I will be doing this when I get home from Iraq. At least the air is cold while she is driving. Still hot as you know what in AZ! Thanks for the info yall!
New User
Joined: Jun 2013
Posts: 1
Likes: 0
This thread deserves a bump as summer is upon us. It's such a great feeling being able to fix it yourself with such an easy fix. I just wanted to add that I did swing my degas resivouir to the side by undoing the three bolts and disconnecting the return hose. It just made accessing the clutch that much easier. Thank you so much Pop for the info.
Freshman User
Joined: Nov 2005
Posts: 25
Likes: 1
From: Russellville AR
Two thumbs up!
My 2001 was blowing cold over 2000 rpm but would turn warm at lower rpm. Googled and found a thread here with the same symptoms. That thread was linked to this one(thanks to PaysonPSD and SpringerPop). I removed the one shim in mine and all seems to be good to go!
My 2001 was blowing cold over 2000 rpm but would turn warm at lower rpm. Googled and found a thread here with the same symptoms. That thread was linked to this one(thanks to PaysonPSD and SpringerPop). I removed the one shim in mine and all seems to be good to go!
New User
Joined: Dec 2013
Posts: 4
Likes: 0
hey guy great info on this thread and forum.. FTE has helped me get my X back on the road much cheaper then overpriced dealers over charging.. my question is i have 2000 v10 X for a few years my ac would start to cycle off and on as i leak freon but cant fin the leak.( have taken it to couple different ac people) the leak wast bad at first have to recharge a little every year..but my question is that my truck didnt get drove very much this last year and now its back going when i turn AC switch on nothing happens blows hot i dont hear ac clutch engage. what should be my steps to get back my cold air? as im moving to tx and there heat is horrible! i will look at the air gap on clutch but as it doesn't even try to engage im not sure if this is only this wrong would there being no freon in the system cause the clutch to not cycle? any info is greatly appreciated thank you
2000 X V10
Rear ac as well idk if this makes a difference
2000 X V10
Rear ac as well idk if this makes a difference
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
Just try the fix, Jwagen. It is free. There is a link to a video in the Tech Folder on how to do it.
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Logistics Pro
Joined: Apr 2010
Posts: 4,446
Likes: 26
From: Panama City, FL
I just replaced my vacuum solenoid today and it fixed half of my ESOF problem. The pump wouldn't come on so that's why I replaced it. Now it comes on and shuts off after the reservoir is filled up but my A/C still defaults to defrost when switched to 4x4. So I pulled a vacuum from the hose in the wheel well to the hubs and the drivers side would pull 16 but would slowly drop to 0 psi and the passenger side pulled 0 psi. So I'm guessing my hub seals are bad and need to be replaced, is this correct? A/C works fine in 2wd, its just when I put it in 4x4. I have Goochs procedures on how to replace the hub seals. Also it will be a good time to rebuild/clean the hubs.
New User
Joined: Dec 2013
Posts: 2
Likes: 0
A/C Clutch Won't Engage
New poster, great thread. Hoping someone might have an idea. 2001 350SD V10 with 170k. Bought it from original owner. A/C clutch will not engage. I suspect some problems in the past because the clutch connector was off the compressor and zip tied back. So, I plugged the connector back in. No change. Checked the voltage at the comp clutch connector - no voltage on gray/white wire, but good ground. Checked the R134a pressure, appears OK. Regardless, pulled the low pressure switch connector - has 12volts. Still, I jumpered it - no clutch. Pulled the high pressure switch connector. Same story - 12 volts. So next I went to the clutch relay in the underhood fuse box. Pulled the rely - has both 12volt command on power and 12volt supply power. Still, I tried jumpering across the relay - no clutch. All I can think is that there is a break in a wire somewhere, but where. Does someone have a good wiring diagram? The Chilton manual is of limited help. From the clutch relay in the fusebox, does the wiring go to the low pressure switch and then to the comp clutch?
Or am I missing something here? Is there something else to check?
Thanks.
Or am I missing something here? Is there something else to check?
Thanks.
Senior User
Joined: May 2010
Posts: 396
Likes: 3
From: Los Angeles, CA
Last edited by thordehr; Jun 5, 2014 at 11:54 PM. Reason: Found it!
Senior User
Joined: May 2010
Posts: 396
Likes: 3
From: Los Angeles, CA
Hey Pop, do you have it for a 99? Probably the same but just in case.
Also, in my printed manual under roadside emergencies, I don't see the relay for the AC clutch. I do see the blower relay being under the hood but not an AC clutch relay.
My AC cut out the other day during operation and a quick check tonight does not get the clutch engaging with key on and selector cycled to ac and back.
I do have a gap of 24 thou so that will have to be brought back to 2-3 thou but seems I'm not getting any attempt at engagement.
Could also be a low charge, I've had issues with a spring-lock connector leaking and maybe the charge dropped low enough that it's not allowing the clutch to attempt to engage even with key on engine off.
I'm mostly curious about the AC fuses and relays since I'm not seeing them in my fusebox diagrams.....
Also, in my printed manual under roadside emergencies, I don't see the relay for the AC clutch. I do see the blower relay being under the hood but not an AC clutch relay.
My AC cut out the other day during operation and a quick check tonight does not get the clutch engaging with key on and selector cycled to ac and back.
I do have a gap of 24 thou so that will have to be brought back to 2-3 thou but seems I'm not getting any attempt at engagement.
Could also be a low charge, I've had issues with a spring-lock connector leaking and maybe the charge dropped low enough that it's not allowing the clutch to attempt to engage even with key on engine off.
I'm mostly curious about the AC fuses and relays since I'm not seeing them in my fusebox diagrams.....
Hotshot
Joined: Jan 2004
Posts: 19,763
Likes: 1,081
From: St Louis
The 99 SD didn't use a relay, the clutch was controlled directly by the series circuit of the fuse (F24 in the CJB), the MODE switch, the low pressure cycling switch, and the high pressure containment switch.
Check the fuse first.
Because the cycling switch has to carry significant current, it's usually the first thing to go. You can temporarily unplug the connector from the switch and jump the two connector pins to see if the clutch energizes. If it does, replace the switch. Same for the high pressure switch.
In 2000, the gas Super Duties went to the PCM-based relay-controlled scheme. The diesels stayed with the simpler switch setup all the way through the 2002 MY and didn't switch until the 2003 MY.
Check the fuse first.
Because the cycling switch has to carry significant current, it's usually the first thing to go. You can temporarily unplug the connector from the switch and jump the two connector pins to see if the clutch energizes. If it does, replace the switch. Same for the high pressure switch.
In 2000, the gas Super Duties went to the PCM-based relay-controlled scheme. The diesels stayed with the simpler switch setup all the way through the 2002 MY and didn't switch until the 2003 MY.