AC Problems!!!!!!

[Super Kaz]

Originally Posted by sirnunya

I had the same problem kinda. fixed it by replacing the low pressure switch and taking a shim out of the compressor clutch. I would try the low pressure switch first..

Ill give that a try. I'm guess I have to drain the system first?

[willypscustoms]

i too have the same problem but i replaced the low pressure switch and it still does it. my ac blows really cold when it works but when i stop or slow down the compressor clutch disengages then it blows warm then when i start driving again the clutch re engages. is this a compressor problem or a clutch problem when the clutch is engaged the ac blows relay cold. and sometimes it works when im stopped and other days it does not work when im stoped.

[super_stroke]

not to get off topic but, 99 and up brake booster's are hydro boost. you can trace the hose's from the booster to the power steering pump. they use the power steering pump to get hydraulic assist instead of the vacum assist on gas and earlier diesel's. that's why it's some time's hard to turn the while while trying to park or back up wwith the brake pedal pused down. the vacum pump we have on our truck's is used for ESOF 4X4 and the A/C and heater control's.

super kaz, there is supposed to be a schrader valve inside the pipe where that switch goes. the switch pushes down on the valve as you tighten it opening the valve. this allows replacement of the switch with out evacuating the system and recharging. give the service dept. a call to make sure tho.

[Super Kaz]

Thanks Super_Stroke I'll check into that.

[lkub65]

Thanks for all of the great info guys! This Texas summer is getting worse so this is what we have found so far........

yep, the vacuum doesn't control if it blows hot or not, today when we got home he told me that at one point when he stopped the a/c clutch wasnt engaged and the compressor wasn't running. I told him about all of y'alls wonderful ideas and we pulled the connector for the low pressure switch and used some stuff we use in the electronics industry called deoxit which is used to clean electric connectors. So far so good, I took it down the road and it never stopped blowing cold air once in the 45 minute drive.

will keep you posted at to if it comes back or not.

[bryanbrown]

Originally Posted by willypscustoms

i too have the same problem but i replaced the low pressure switch and it still does it. my ac blows really cold when it works but when i stop or slow down the compressor clutch disengages then it blows warm then when i start driving again the clutch re engages. is this a compressor problem or a clutch problem when the clutch is engaged the ac blows relay cold. and sometimes it works when im stopped and other days it does not work when im stoped.

That is exactly what mine does. What makes the clutch engage? Where is the low pressure switch?

[sirnunya]

There is a shrader valve so there is no need to evacuate for the low pressure switch replacement. Cleaning the connectors also helps I noticed. Mine was intermittently working and not working so I ended up replacing it. Also when my clutch would shut off, I could physically push the AC clutch and it would engage, so the shim that was behind the pulley was worn down. Took it out and compressor engages and disengages when it should now.

Low pressure switch is on the passenger side on the side of the evaporator near the bottom.

[Bronconut]

Okay, I noticed that when mine is blowing cool (not cold), the a/c compressor is engaged. So would my problem be the switch?

[WILLIAM LORCH]

Bronconut:an all folks interested, Ill bet your refergrant gas is low!! Im not sure what to say here wish there was a spot where i could write up a short A/C corse for all interested... Believe me wen i say this is a closed system there is NO reason 4 the gas to escape. Look around all the connections in hte system for oil leeks,with a ford it is mostlikley the compresser seal leaking, Look very carefullly behind the pulley on the compressor..
Now just adding refergrent will patch it . IT WILLNOT fix it!!!!!! It is a bandaide 2 say the least. Get a electronic sniffer!!!! or the eyeball looking 4 oil that is carried in the refergent.. ohter way is add some dye wen you add referegent, (i like this one my self and i use a black lite), Sorry for takeing up so much space an being so windey but there is just SO MUCH misconceptions an gesses with A/C it drives me crazy having lotsa folks get ripped off by the so called a/c Xperts......<<<<<<<<<< Bill>>>>>>>>>> Remeber You should never have to add gas if u do the system has a leek FIND IT!!!!!!

[1hotsuperduty]

I have the same problem that I have seen posted by others here. The issue with the a/c blowing hot air when it should be blowing cold! I have heard it is an issue with a vacuum check valve which keeps the cold air flowing thru the system. If you rev the motor during this HOT flash of air, you will hear the door slap shut and the cool or cold air will flow once again. This seems to be a serious problem with ALL of the diesel for trucks from this same period. I suppose since it is not a safety issue, the will never be a recall on the part causing this problem.