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Nowabeachbum · 10-30-2011, 10:31 AM

Quote:

Originally Posted by ga traveler

Your static pressure is too low to turn on the pressure switch. You have a pressure switch that will not supply 12v to the compressor if the freon is too low. you DO NOT have a compressor problem. Add freon until the switch comes on or jumper out the switch to add freon. Of course hook up the switch again when the pressure comes up.

X2
Until you engage the compressor, you do not know if the compressor is bad. I bet it is fine.

sCarycary · 10-31-2011, 11:41 AM

First thanks for all of the replys. The a/C clutch is not bad. I went back and rechecked the voltage to the clutch. Now it reads +8.25VDC. Correct, not enough to energize the clutch. I used a separate battery at +11.5 volts and that is enough to energize the relay. I still only got around 45psi on the low side and the high side. Ambient is 70 degrees. 45psi should be enought o close the low pressure switch. Yes, the low pressure switch is in the high pressure side. I did find when I wiggled the temperature switch on the air box(passenger side on the fire wall in the engine bay) the compressor would energize. It still blows 90 degree air. I am confused by the same pressure reading on the low as the high side even with the compressor running. I did try adding R134a. Pressure went up from 40psi to 50psi. Anything more than that is over charged I believe, unless of course it is really hot outside. I'm getting close to taking it to a shop that can fix it. After reading about the one guy that was $1,500 into getting his fixed and it still doesn't blow cold air for more than a day or scares the $$$ right out of me. I don't want to end up in that situation. Whew!

Nowabeachbum · 10-31-2011, 11:44 PM

If your ambient is 70, your static pressure should be right at 70 lbs. (check the internet for an R12 or R134a pressure-temperature chart). Are you sure what kind of refrigerant is in your rig. Unless it was changed, it should be R12. As stated before, your static pressure should be 70 lbs at 70 degrees. I don't understand how you can have a compressor that turns and isn't making an incredible amount of noise not creating a pressure differential. If you do have a pressure differential with the compressor running, then I think you are still light on refrigerant.

tkolbe · 11-02-2011, 05:00 AM

I tend to think you do have a bad compressor (bad valves). Even if the system were empty, when the compressor is running you would see a pressure differential. You would pull a vacuum on the suction side. Also, I dought that your system has R-12, it has not been used since the early 90's. That being said, changing a compressor is not a normally a do it yourself job. It requires some equipment, vacuum pump, gauges, etc. that most people don't have laying around. I would have it checked by a professional, might be cheaper in the long run.

melvonnar · 11-02-2011, 07:38 AM

Quote:

Originally Posted by tkolbe

I tend to think you do have a bad compressor (bad valves). Even if the system were empty, when the compressor is running you would see a pressure differential. You would pull a vacuum on the suction side. Also, I dought that your system has R-12, it has not been used since the early 90's. That being said, changing a compressor is not a normally a do it yourself job. It requires some equipment, vacuum pump, gauges, etc. that most people don't have laying around. I would have it checked by a professional, might be cheaper in the long run.

Most charge a flat fee to check the system

DesertRhino · 11-03-2011, 07:10 AM

Quote:

Originally Posted by tkolbe

I tend to think you do have a bad compressor (bad valves). Even if the system were empty, when the compressor is running you would see a pressure differential. You would pull a vacuum on the suction side. Also, I dought that your system has R-12, it has not been used since the early 90's. That being said, changing a compressor is not a normally a do it yourself job. It requires some equipment, vacuum pump, gauges, etc. that most people don't have laying around. I would have it checked by a professional, might be cheaper in the long run.

Now that you have gotten the compressor to run and there is no pressure differential at all when actually running, I believe tkolbe has the correct diagnosis. The valves in the compressor are probably shot.

ga traveler · 11-04-2011, 12:28 PM

If you decide to take it in for repair, some free advice. DO NOT go in and say I tried to fix it and I think it is a bad compressor. Tell them you cousin looked at it and said it is low on freon. If they think you are already expecting a high dollar repair, many shops will see to it you are not disappointed. Act like you are expecting a low dollar repair. Most shops are honest but a lot of them will charge as much as they think you will bear.

tkolbe · 11-04-2011, 04:01 PM

I'm going to expand on my earlier comment, just for the sake of DIY education. If by chance you try to install a new compressor, it is possible to destroy or damage the compressor by improperly charging the refrigerant. Flooding the compressor with liquid refrigerant can damage the valves and / or break the piston. This can also be done by just adding refrigerant to a low charge. Be careful!