bobdole369

OK, so after trolling the boards for a bit, and with a little help from Autozone.com "vehicle repair guides" that supplied a very complete and thorough wiring diagram, I was able to troubleshoot and make my A/C work! WOOHOO! Happy Wife! Cool car!

My A/C suddenly stopped working mid-drive one day about 2 years ago when I had the defroster on. I could instantly tell the compressor had turned off as the car was suddenly more responsive and the defroster wasn't working well anymore (it was raining at the time), it was blowing, just wasn't clearing the windshield. I didn't really know much about HVAC at the time, so I figured I blew the compressor or maybe a fuse somewhere. It was early fall, so I figured I could wait a few months to get it fixed, and wasn't looking forward to the several hundred dollar repair bill. A few months turned to a year, a hot summer in 2004 was no trouble (2-75 A/C system now), an even hotter one in 2005 no problem (worked closer to home, commuted early morning and late afternoon, but lunch was a b**ch). This year I'm driving far and my wife needs the car too so its time to fix it already.


Started the car, turned the A/C on, looked at the clutch and it was NOT spinning (as it had been in its nonworking state for the past 2 years.)

I started by checking the A/C-Heater fuse under the dash, 25A, It was good. I had +12V across this to ground, 0V on the other side of the fuse. Looking good so far.

I jumped the low pressure switch connector at the accumulator (grey tower on the passenger side of the engine compartment, the connector is a black rubbery boot) The switch is inside the accumulator and looks kind of like a 120V outlet plug. 2 metal tabs. The connector side (the rubber boot) is what your supposed to jumper to test for the pressure switch malfunction. This switch is normally closed, and opens when the pressure on the low side of the system gets too low. No change when I jumpered the low pressure switch. I had +12V on one pin of the connector, and 0V on the other side. With my meter I measured 0.8 ohms at the low pressure switch. OK so that looks like it isn't the reason my A/C isn't working. It *could* still be bad, if the switch didn't open if the pressure got low, but I have no way to test that. On to the high pressure switch.

Its located on the rear side of the compressor, its a roundish plug on the top side, easily accessible. Its held in with a plastic latch on the underside. It easily came out. I jumpered this connector, and watched and heard my A/C compressor clutch engage and spin the compressor! WOOHOO! Problem found! I go in the car and its blowing nice and cold! Excellent. I measured the pressure switch and I got 0.7 ohms. Hmmmmm. I removed the jumper and plugged it back in, the compressor stopped spinning until I tapped the connector, then it turned on and off again! Bad connection. I inspected the female pins of the connector which looked mostly OK, a bit flayed, but then again my car IS after all an old ****, so I used a pick to *carefully* compress the connector a bit, it cracked....... doh! Still serviceable, but lets try. Now when I put it in it cycled the compressor a few times, I put stress on the connector and it stayed on until I removed my finger. Not good enough it would seem. Fearing I'd break the connector I went the other way. Using my trusty pick I gently moved the thin male pins of the switch inwards. Now when I plugged it in it stayed on! SUCCESS! Stress didn't change anything,

I drove the car about 4 miles with the air on, it was beautiful and nice and cold again.

Afterwards I found a lot of condensation on the accumulator and also on the upper line leading from the condensor in front of the radiator to the condensor. Is that much condensation normal in just 4 miles? It was beading up and dripping off the whole accumulator and line. (I do live in south FL, it was 86 and had just rained today so it was very humid) The other line from the condensor was hot, not too hot to burn and blister, but too hot to hold tight.

OK, so now that I've had 2 years without turning the A/C on what do I need to check to make sure I don't screw it up now that its working again? The system is R-134A retrofit right before I got it. I don't know the quality of the retrofit. The compressor is a Delco that looks original. Accumulator is 3 years old - new when I got the car 3 years ago, and the air worked fine for a year when I first got it, so basically we're talking 3 years on an accumulator, and an original compressor.

I imagine I should spend some money on a set of gauges to check the freon low and high side pressures. I've heard 190-250psi is normal on the high side, and 40-70psi on the low. Is that correct?

I don't think there is a way to check oil level, short of evacuating and refilling right? Thats something I think I'd like to do.

I heard something about an adjustable orifice tube for colder air. Is that something I want to try to do knowing nothing about HVAC (and having few tools of it) other than the electrics? I imagine I'd have to evacuate the system to do that so perhaps I can buy the part and instruct the guy whos going to do the evacuate and recharge (with oil) to put that orifice tube in?

Now as far as repairing the problem "more" permanently. I suppose a junkyard would have the connector, but I fear it would be old and brittle like mine was. Anybody know where to buy just this connector new? And how about the switch itself? How hard would it be to replace? I think I'd like to get a new accumulator while I've got the system evacuated. Do they normally come with a new low pressure switch as well?

rideon1200

If it is the original compressor it was a back yard conversion. The compressors are changed out for an professional conversion due to the gasket make up in a R12 system. Also there is no reason to check the oil in the system. As long is the compressor is running dont worry about the charge. Dont try to fix what isnt broken.