A/C sometimes cold-other times not

dklitzke

Registered User
I have a '95 SC with about 170k on it and am experiencing A/C inconsistency. It stopped working back in April, and my mechanic diagnosed it as a leaking line, the front-most one ($300 to fix-ouch!). Then a few weeks ago it began doing the same thing, blowing warm, so I took it back under warranty. Well, now they tell me it's the valve in the compressor to accumulator line, which requires the whole line to be replaced at a cost of $300 for the part and $200 more for labor. I said yeah go ahead, but they had to order the part, only could find one in Las Vegas. Well I have waited for over a week, so just for kicks on Sunday, I decided to try the A/C and it worked really well all day in some pretty extreme heat & humidity. Then it stopped again yesterday, but now it's cooling today. I really doubt if a valve in one of the lines is causing the problem. Any thoughts? Thanks in advance.
 
Is the compressor kicking on when it blows out hot air? If it isnt, then i would probly lean more torwards a bad low pressure switch. If it does, then yea, its probly on its way out.....


Derek
 
hmmm, tell me more about the low pressure switch

Not sure about the conditions you described beloww, but I assume that switch you are talking about is not a $300 part?
 
No, this low pressure switch is not a 300 dollar part. What this switches job is, is when the pressure gets to low, due to a leak or what not, it wont let the compressor kick on. SOMETIMES, those switches go bad and wont let the compressor kick on. The one of my truck has been bad for years, but ive just by passed it.......
 
Do a "wiggle test"

If the A/C is on and blowing hot air, wiggle the connector for the pressure switch to see if the compressor kicks on. The sensor is located on top of the accumulator/dryer (the sealed aluminum can with two curved "pipes" that connect to the refridgerant lines). When my switch went bad I could tap it with the handle of a screwdriver and the compressor would kick on. If the switch is the problem, it's an easy fix (and fairly cheap too)...
 
I just went through this with my 94 SC. Last summer it started blowing warm sometimes and blow cold at other times. By the end of summer it just blow warm air and the compressor wouldn't kick in but I didn't bother with it untill it started getting hot out around here this year. I got lucky because all it was was the A/C cyclic switch located on top of the accumulator/drier. If your A/C compressor is not kicking in I would try replacing that switch first as others have said. BTW, before I replaced the switch I tried tapping on it and a few other things but the compressor never would kick in
 
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I just had this same problem on my 93. The pressure switch on top of the accumulator was not making good contact. Pulled the plug & cleaned the contacts on both real good with an emery board, applied a bit of dielectric grease and plugged it all back together. So far it has performed flawless this summer.
 
IF it is properly charged, and the pressure switch is ok, be sure that the clutch airgap is right. On a higher mileage vehicle, often the clutch disc can wear, causing the airgap to open, due to the loss of material. think of it like a regular clutch, each time it engages and dis engages, it wears just a bit. If it wears to a point that the gap becomes too wide, it can't engage because the magnetic field cannot pull it in. Without looking up exact specs, almost all compressors are about .020 inch gap. Gap is measured by sliding a feeler between the clutch disc and the pulley (obviously engine off!). OR, lacking a feeler, with the engine running, tap the disc towards the compressor with the end of a screwdriver handle, being careful to NOT get the driver caught in moving parts. IF it engages, the gap probably needs adjusted.
 
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