1994 air conditioner problem
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From: franklin in
1994 air conditioner problem
i have been searching but cannot seem to find the fix to my problem. i bought a 1994 last year that had been wrecked and stored for a couple of years. i tried to turn on the air conditioner but the compressor would not turn on. hooked up gauges and found the system had no pressure. vacumed down the system and let set for an hour and it held vacum. tried to jump the pressure switch so i could put in the oil and freon but it would not start compressor. tested the plug and had power to the gray wire(although the test light was very dim) pluged the switch back in and tested the plug at the compressor and had no power. jumped the compressor plug with 12 volts and the compressor started. let it run while i put in the oil and 3 cans of freon. pluged compressor back up and it still will not run by itself. if i jump it it will run and cool the car fine. what am i overlooking? the car has the manual heat and air controls not digital. when the air button is pressed the green light comes on. disconnected the battery for an hour, thouht that might reset system but it did not. thanks for any help
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Do you have the factory service manual? There is much more to these HVAC systems than in the good old days. The FSM should have a diagnostic sequence that you can follow.
With a very dim test light at the Low Pressure switch, it sounds to me like a bad connection somewhere. But it may also be a 5v signal that runs through the computer. That is just a guess. The FSM will be very helpful and worth the price.
With a very dim test light at the Low Pressure switch, it sounds to me like a bad connection somewhere. But it may also be a 5v signal that runs through the computer. That is just a guess. The FSM will be very helpful and worth the price.
Burning Brakes
Joined: Feb 2009
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From: Richmond Virginia
i have been searching but cannot seem to find the fix to my problem. i bought a 1994 last year that had been wrecked and stored for a couple of years. i tried to turn on the air conditioner but the compressor would not turn on. hooked up gauges and found the system had no pressure. vacumed down the system and let set for an hour and it held vacum. tried to jump the pressure switch so i could put in the oil and freon but it would not start compressor. tested the plug and had power to the gray wire(although the test light was very dim) pluged the switch back in and tested the plug at the compressor and had no power. jumped the compressor plug with 12 volts and the compressor started. let it run while i put in the oil and 3 cans of freon. pluged compressor back up and it still will not run by itself. if i jump it it will run and cool the car fine. what am i overlooking? the car has the manual heat and air controls not digital. when the air button is pressed the green light comes on. disconnected the battery for an hour, thouht that might reset system but it did not. thanks for any help
This likely has nothing to do w/AC not engaging at this point since you have it charged BUT the sensor you were jumping sounds like the high side AC pressure switch which has 3 wires one of which is gray and has a 5 volt (your dim test light
) reference signal from the PCM. The switch you would need to jump in a low or no freon situation is on the suction (low side) line at the evaporator--should have 2 wires 1 blue and 1 green/white. Jumping the 2 wires in that connector will usually engage the the compressor if the rest of the system is electrically good and the only problem is a low charge. In your case i'd ck the above fuse and relay first though.
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From: franklin in
thanks for the advice. the fuse was good an the relay has power also. will go back out and look for the other switch and see if it will jump start the compressor. thanks. is the ac relay under the dash beside the steering colum on the 94? found 3 relays there. is it the one on the left as i am setting in the car? thanks again
Burning Brakes
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From: Richmond Virginia
thanks for the advice. the fuse was good an the relay has power also. will go back out and look for the other switch and see if it will jump start the compressor. thanks. is the ac relay under the dash beside the steering colum on the 94? found 3 relays there. is it the one on the left as i am setting in the car? thanks again
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From: franklin in
i found and jumped the 2 wire switch and it will engage the compressor. will try a new switch. thanks for all the help. cant wait to get this 94 out and drive it. i also have a 84 vette and want to see how much better this one is.
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From: franklin in
changed the switch but it still does the same thing. changed the relay also. relay has power to both brown wires. at a loss. anyone have a factory service manual for a 94 for sale or who has the best price on one? are they all the same?
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Burning Brakes
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From: Richmond Virginia
If you jump the connector at the cycling switch and compressor engages--but doesn't engage after replacing the switch then it sounds like you have a low charge to me. I know you've charged the system from reading a previous post. When the connector is jumped is the vent temperature COLD or just cool and what do you have for pressures on the gauges?
As far as FSMs go try ebay they usually can be had there for most C4s.
You'll want the two volume set (more info in these) and not the single preliminary edition.
As far as FSMs go try ebay they usually can be had there for most C4s.
You'll want the two volume set (more info in these) and not the single preliminary edition.
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From: franklin in
when i first charged it by jumping the compressor i put i themometer in the vent and had it down in the 50s. i am going to borrow the gauges sunday to check the pressures again. when i first vacume it down it hel vac for an hour so i did not think it ha a leak but will check in the morning. thanks again
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From: franklin in
put the gauges back on and had zero pressure. do not understand why it held a vacum for an hour. took the pressure switch off and it was off for over a day. wondering if the shrader valve was leaking. going to wait until its dark to look at it with a leak dectector kit.
Melting Slicks
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From: Palmdale CA
But, while Pressurized with Freon, there is 30-250psi pushing outward. It would be best to do a partial freon fill, and then perform an Bubble/Halogen leak check on the intire system before topping off with freon.
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From: OK
Did you clear any HVAC trouble codes (which would be 09 for low freon pressure)? The compressor won't engage if that code has been set, if the manual has the same function as my 93 electro AC. The suggestion to disconnect the battery will clear the HVAC trouble codes and allow the compressor to engage if everything else is okay.
You can check the schraeder valve by squirting a little soapy water on it (like 409 spray cleaner).
Trouble shooting the HVAC can be a nightmare. If you dont have a set of manuals, you are going to be an unhappy owner, either through frustration or maintenance poverty.
Bob Thomas 40th coupe
who has spent many days under the hood lately TS the HVAC in his car
You can check the schraeder valve by squirting a little soapy water on it (like 409 spray cleaner).
Trouble shooting the HVAC can be a nightmare. If you dont have a set of manuals, you are going to be an unhappy owner, either through frustration or maintenance poverty.
Bob Thomas 40th coupe
who has spent many days under the hood lately TS the HVAC in his car
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From: franklin in
i found with the help of a dye kit the compressor looks to be leaking. i suppose from sitting the last couple of years the seals must have dried up. thanks to everyone for trying to help.
1994, 93, 94, ac, air, airconditioner, c4, clicking, compressor, conditioner, conditioning, corvette, jump, problem, start, troubleshooting
