AC problem
Thread Starter
5th Gear
Joined: Jul 2009
Posts: 5
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AC problem
93 Vette, 134 convert (sticker says so) Compressor does not come on. No cold air
All Fuses pulled and checked.
Pressure guage on can says 50 psi.
no voltage at the compresor connector
I checked the low switch looks ok 12v and jumpered it nothing
High switch has 3 prongs not sure how to check it
I pulled the clutch relay, coil is 90 ohms, 12v is available on both the coil and the switch side but something must need to put a ground then on the opposite side of the coil.
Whats next?
All Fuses pulled and checked.
Pressure guage on can says 50 psi.
no voltage at the compresor connector
I checked the low switch looks ok 12v and jumpered it nothing
High switch has 3 prongs not sure how to check it
I pulled the clutch relay, coil is 90 ohms, 12v is available on both the coil and the switch side but something must need to put a ground then on the opposite side of the coil.
Whats next?
Thread Starter
5th Gear
Joined: Jul 2009
Posts: 5
Likes: 0
more info
I pulled the fuses to reset the computer. Started the car and the AC kicked on. It short cycled with the compressor on for less then 1 sec several times and then quit trying. I checked the pressure and it would drop to 30 lbs or so from 50 when the compressor was on. I've repeated this a few times just to be sure. pls help!
Thread Starter
5th Gear
Joined: Jul 2009
Posts: 5
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more info
read how to check the codes... did so and I have a code 9. I'm afraid tho of the pressure that I'm seeing on the low side that I might damange something... Can someone reassure me that I'm doing the right thing by adding more freon.
Drifting
Joined: Jun 2007
Posts: 1,261
Likes: 2
From: Prather, California -1990 ZR-1 White/Flame Red- -SOLD!!-
Sounds like you just need a freon charge. Is your A/C system still R12 or has it been converted to R134A? I converted my '93 to R134A and it works nicely.
I have found that when the freon is low, the compressor will cycle quickly like you said, 7-8 times. After that, it shuts off (to protect the compressor/clutch) and compressor won't try to engage again until system is reset (disconnect battery).
Find out whether you have R12 or R134A and put some more freon in until the clutch stops cycling and stays on. When your charging the system, you can't let it get to that 7th or 8th on-off cycle or the a/c clutch won't engage till you disconnect then reconnect the battery to reset the a/c system again. What I do is just turn off the a/c before it gets to the 7th on-off cycle so I don't have to disconnect the battery, then I turn the a/c on again. I keep doing that until the clutch stays on. You also may have a leak in your a/c system which let the freon out in the first place, which you will need to find.
The correct pressure will only show when the compressor is spinning. When the compressor turns off after it was just on, pressure will appear to go real high, but that is normal
I have found that when the freon is low, the compressor will cycle quickly like you said, 7-8 times. After that, it shuts off (to protect the compressor/clutch) and compressor won't try to engage again until system is reset (disconnect battery).
Find out whether you have R12 or R134A and put some more freon in until the clutch stops cycling and stays on. When your charging the system, you can't let it get to that 7th or 8th on-off cycle or the a/c clutch won't engage till you disconnect then reconnect the battery to reset the a/c system again. What I do is just turn off the a/c before it gets to the 7th on-off cycle so I don't have to disconnect the battery, then I turn the a/c on again. I keep doing that until the clutch stays on. You also may have a leak in your a/c system which let the freon out in the first place, which you will need to find.
The correct pressure will only show when the compressor is spinning. When the compressor turns off after it was just on, pressure will appear to go real high, but that is normal
Last edited by bdw18_123; Jul 23, 2009 at 05:27 PM.
Thread Starter
5th Gear
Joined: Jul 2009
Posts: 5
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fixed
1 Can freon... What had me fooled was the compressor not running at all at the beginning. I didn't realise the system would fault out and not allow the compressor to run. I added freon and started the engine and alllowd it to run for a few compressor cycles, stopped the engine before it faulted and then started it again. Is it normal for the compressor to run continously or does it still need freon?
