Here's what my A/C is doing wrong...

Aug 05, 2004 5 Replies
H

Works fine for 5 or 10 minutes, then stops working. I had it checked and the guy said it has the correct amount of refridgerant. He could not get it to fail at his place though. Here's a couple more specifics:



when it is in it's failure mode, IE engine is running and the dash control is set for A/C and it blew cold and then stopped working, if I pop the connector off the high pressure switch the switch shows continuity. If I pop the connector of the low pressure switch, same thing. Does this tell anyone anything?



Generally speaking the vehicle needs to sit a while before the A/C will work again. Just leaving the dash sontrols set to A/C does not work; you can drive for an hour and still no A/C.



ANy ideas? WHat else can I check?


-jeff


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J

Check the high side pressure in the failing mode. If it's too high then it's most likely a stuck/clogged expansion valve.

JoBo

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B

You didn't mention what kind of vehicle you're talking about, but here's a guess.

Probably a failing A/C clutch. Many times they will work at first, then after cycling off, fail to re-engage when cycled back on. A weak clutch field, too large of an air gap or just plain worn out.

Next time it's in fail mode, give the compressor a tap near the clutch. It may get the clutch to engage. If it does, you've found the problem. Another way would be to unplug the clutch field and check for power while in fail mode. Just watch your fingers around the belt and other moving parts. 1st test is the easiest, but not always conclusive if it fails to re-engage.

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H

That's interesting... but i don't think it's hot, unless the temp sender is bad. It stays just under 210 pretty much all the time...

-jeff

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H

Yeah, I realized that about the time i hit "send"... it's a '97 TJ with the

4.0L and a manual tranny. The A/C is factory original, vehicle has 85K miles.

I'll give it a whack, literally! Thanks.

I assume there's a pretty obvious electrical connector at the clutch? I'll give it a try.

Thanks!!

-jeff

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