AC Help. Correct pressures?
Hotshot
Joined: Dec 2012
Posts: 11,278
Likes: 1,658
From: Las Cruces New Mexico
Brandon,
Thanks for your thoughts. I didnt test equalization...but I will.
It happens when Im on the move or idling. It randomly stops blowing then starts again minutes later
Why did you have no fan on your truck????? I only have the huge clutch activated fan. I dont believe I ever seen a separate AC fan come to think of it.
Thanks for your thoughts. I didnt test equalization...but I will.
It happens when Im on the move or idling. It randomly stops blowing then starts again minutes later
Why did you have no fan on your truck????? I only have the huge clutch activated fan. I dont believe I ever seen a separate AC fan come to think of it.
If it just stops throwing cold good chance it's the compressor clutch is disengaging, removal of shim might potentially work.
If no air out vents, check for vacuum leaks also if your truck is equipped with the automatic locking hubs and use 4x4 your and have leaks the AC will default to defrost.
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Cargo Master
Joined: Aug 2011
Posts: 2,319
Likes: 89
Air blows but suddenly goes to ambient temp. Praying for a simple clutch fix. Waiting on ECU to comeback from repair so I can try it.
I have manual locks...wish I had automatic units...I hate getting out to lock dem hubbies.
I have manual locks...wish I had automatic units...I hate getting out to lock dem hubbies.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
Idk, when you know you gotta lock'em in you tend to plan for it and pick somewhere clean and convenient to do it. The autos always seem to pop a vacuum leak in about the deepest nasty hole you could find.
Butt-Head
Joined: Apr 2004
Posts: 9,457
Likes: 2,938
From: Reed Point, MT
The PCM doesn't have control over the compressor.
Given the symptoms listed, either the clutch air gap is too wide or the terminals in the high pressure switch (by the oil dipstick) are fried.
Given the symptoms listed, either the clutch air gap is too wide or the terminals in the high pressure switch (by the oil dipstick) are fried.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
Then what kicks the AC off when the engine starts getting too warm? I've seen it happen on a friend's 99 SD pulling a Aload through rolling hills at lowish rpm's. If it wasn't the PCM stepping in to shut down non essentials then any ideas what might cause it?
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Cargo Master
Joined: Aug 2011
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I need it to start the truck.....
Butt-Head
Joined: Apr 2004
Posts: 9,457
Likes: 2,938
From: Reed Point, MT
The only things dictating compressor clutch operation on a 1999-01 7.3L are the low pressure switch on the accumulator side, the high pressure switch on the compressor discharge side, and the fuse/mode selector switch. Anything temperature related would be caused by high refrigerant pressure (hot condenser), compressor clutch coil high resistance, or bad terminals in the high pressure switch.
Oh, and I lied. Starting in 02, the PCM does have control over the compressor. It still uses the same high and low pressure switches but they are PCM inputs and the brain makes the determination based on those. However, the chances of the PCM losing ability to run the compressor relay are pretty slim and I wouldn't start there with diagnosis.
Banned
Joined: Dec 2018
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I've ran around without the fan for awhile on a couple of occasions but it's not advisable. #1 the A/C wont work while parked or moving slowly and #2 the motor will get too hot if you start asking it to do anything harder than putt down the road unloaded. Not watching oil temp with a PID monitor would be a no-no.
Banned
Joined: Dec 2018
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Are those pushing from the front or pulling from behind?
Money no object I'd rather have a Horton clutch on a rocker switch in the cab. I drove a Kenworth a couple times that had that and thought it was cool (hah...) being able to control the fan manually. It would actually help engine braking going down a hill too.
But TBH back when my A/C still functioned and the condenser and fan clutch was brand new, it blew pretty damn cold while parked with no special mods or massages to boost performance. If it keeps one of those blue shop paper towels sucked up against the condenser it's getting plenty of airflow from the fan.
Money no object I'd rather have a Horton clutch on a rocker switch in the cab. I drove a Kenworth a couple times that had that and thought it was cool (hah...) being able to control the fan manually. It would actually help engine braking going down a hill too.
But TBH back when my A/C still functioned and the condenser and fan clutch was brand new, it blew pretty damn cold while parked with no special mods or massages to boost performance. If it keeps one of those blue shop paper towels sucked up against the condenser it's getting plenty of airflow from the fan.
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Joined: Jan 2005
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From: Henderson, NV
They push from the front. There is not enough room between the condensor and intercooler for fans.
Lead Driver
Joined: Aug 2022
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From: Oologah, OK
they MUST be on the back side, to pull air through the fins....
I tried that on my Suburban with an extra ATF cooler, in Suction Mode, the fan pulled air like gang buster. but it won't fit snug against the AC condenser, so I reversed the Polarity, and turned it around. didn't work worth a damn, barely pushed any air through at all.