AC blowing warm air

[Y2K 281]

Hey Guys,

I've been reading up on some AC fixes for when it begins to blow air and have knocked a few items off the list. Basically as far as I know the AC all of a sudden began blowing warmer air. Took a look at the compressor clutch and it wouldn't move with the ac on. I first checked all of the fuses and all of them were fine. I then went out and got a refill kit with gauge to test pressure. My first test of pressure showed 25psi while the car was running on max cold. I then added a bit in since it was a hair on the low side on the gauge and nothing changed. I then ran a jumper wire on the low side switch and the clutch kicked right in. I just replaced the low side switch from ford and now the clutch kicks in but it cycles on for about 1.5 seconds then turns off and does the same thing every 5-10 seconds or so. I went back into the car the ac doesn't feel that cold. Put the pressure up to about 35/40 psi and it continues to cycle from 45psi to 25 psi in that second or so the clutch cycles and then it shuts back off. Was wondering what else can be causing this problem.

Thanks for the help.

Need this fixed before the knotts trip next week.

 

[COramprat]

Clutch may be going bad. Is it noisy at all?

 

[4.6andSlicks]

I believe this is usually caused by low pressure. The gauge set you hook up is to measure pressure while the compressor is running. If you add refrigerant and then wait, and the length of run time of the compressor becomes longer, you're definitely low on refrigerant.

I don't see you're location in your profile but a HVAC guy once told me not to do anything with your AC until the temp is over 70 degrees. I messes with the pressure readings.

 

[Gearbanger 101]

Compressor kicks on and off means there's not enough pressure, IE : Not enough coolant in the system....keep pumping. You've obviously got a leak somewhere. Usually the O-rings on the quick connect. A/C issues can be a real PITA to diagnose.

 

[Y2K 281]

What I dont understand is these cars are supposed to be around 35psi on the low side and thats in the green. The pressure right now sits at 40 before the compressor kicks in then fluctuates between 35 and 45 psi. If I fill it any higher it will go into the warning zone. Also after several days the pressure has not dropped one bit since i filled it so how can it be a leak?

 

[Y2K 281]

Ok I just tested it again. The pressure drops to 20psi when the clutch turns on and slowly goes back to 40 when it turns off. The moment it hits 20psi the clutch shuts off. I tried adding more refrigerant to see if it increased the clutch running time but it did nothing. The air blows warm right now and the vent actually runs cooler.

 

[cobra2798]

Im having the exact same problem, anyone have anymore suggestions?

 

[nyuk98gt]

Chaps:

There's a pressure switch up near the firewall that can go bad and cause these problems. I'm sorry but I don't remember the details (I'll look for them) but there may be a simple test (short the terminals? measure the resistance? something else??) to prove that the switch is shot. There is a Schrader valve in the stub so the old switch unscrews and no refrigerant is lost.

Sorry for the poor tech: the only thing I can tell you is the switch may be the culprit. I will try to find a thread or two about this switch.

edit UPDATE: I found a thread or two on MD. If you short the switch terminals the compressor should run (continuously). A new switch will cost somewhere between $11 and $30, depending on where you buy it.
end of edit

Chris

 

[evolucion311]

My car had exact same symptoms, ended up the passenger side valve cover screw gradually rubbed an abrasion into the ac line near the fender well. Use uv dye refrigerant to load your system and then it will vent and leave a dye residue. You will need special disconnects to separate the lines. Replace the broken or cracked components after venting the system releasing the pressure. Then have the system evacuated and recharge it to the appropriate level

 

[Bluestizzy]

My ac clutch stays engauged with the ac on or off. When I unplug the compressor, the clutch doesn't turn (engauge I guess). Any help?

 

[nyuk98gt]

Bluestizzy:

Let me do a little hunting for an answer for you. I wonder if the clutch is stuck in the engaged position (this would be odd, imho).

Stay tuned.

Chris

p.s.--Welcome to StangNet.

 

[Bluestizzy]

Thank's for the welcome Chris. Hope you find something out for me!!!

Willie

 

[Red04GT]

What I dont understand is these cars are supposed to be around 35psi on the low side and thats in the green. The pressure right now sits at 40 before the compressor kicks in then fluctuates between 35 and 45 psi. If I fill it any higher it will go into the warning zone. Also after several days the pressure has not dropped one bit since i filled it so how can it be a leak?

you need to have a Evacuate, Vacuum, leak check and refrigerant recharge performed. it can tell you alot.

 

[nyuk98gt]

Bluestizzy:

PM sent.

Chris