A/C Compressor clutch doesn't engage

[Railroader]

Originally Posted by Ed_Strong

Success... YES!!!
Oh yeah...
I went to the chevy dealer today and requested the "Refrigerant Pressure Sensor" as it's called on this system and they found it! It's not cheap tho, $55.79 and it was back ordered. So, I went to an independent AutoParts store and gave them the AC Delco part number 15-72104 and they were able to find an after market match for $48. I took a bite at the bullet and went for it, installed it right there in the parking lot and bingo, the AC started working again... Thanks to all that help!
I just regret having to retrofit my AC System for no reason, I hope the change to R134 don't give me any troubles in the future. I doesn't start cooling immediately as it did with R12 and even tho the air is cold it doesn't come out freezing cold as it used to before... BUMMER

My son has a 96 with the same problem, Was that the afore mentioned pressure transducer, I need the compressor to run to add freon, seems there should be a way to by-pass that sensor. Thanks

[CDJr]

To force the compressor to run to charge it up, you simply jump out the low-pressure switch. But ONLY force it to run as you are charging it up, as running it while low on refrigerant will burn up the compressor.

[Railroader]

Originally Posted by CDJr

To force the compressor to run to charge it up, you simply jump out the low-pressure switch. But ONLY force it to run as you are charging it up, as running it while low on refrigerant will burn up the compressor.

It doesn't seem to have a low pressure switch.

[Ed_Strong]

Originally Posted by Railroader

My son has a 96 with the same problem, Was that the afore mentioned pressure transducer, I need the compressor to run to add freon, seems there should be a way to by-pass that sensor. Thanks

Hi Railroader:
Are you sure the A/C system is low on freon? Have you checked if the Compressor Clutch engages? I ask because if you have a bad pressure switch (either on the high or on the low sides) on the system the compressor clutch won't engage for anything. My car is a 1991 3.1L V6 and has a continous running compressor with just one transducer (Pressure) switch on the high side.
What I did was, with the engine OFF, I jumped the A/C compressor clutch by running a length of wire straight from the battery into the clutch connector at the compressor. Mine is accessible for under the car, I'm not sure about yours. It should engage right away when you power it, if it doesn't the clutch is bad.
Now you can crank the engine and leave the clutch hotwired so you can add freon to the system

[Railroader]

Originally Posted by Ed_Strong

Hi Railroader:
Are you sure the A/C system is low on freon? Have you checked if the Compressor Clutch engages? I ask because if you have a bad pressure switch (either on the high or on the low sides) on the system the compressor clutch won't engage for anything. My car is a 1991 3.1L V6 and has a continous running compressor with just one transducer (Pressure) switch on the high side.
What I did was, with the engine OFF, I jumped the A/C compressor clutch by running a length of wire straight from the battery into the clutch connector at the compressor. Mine is accessible for under the car, I'm not sure about yours. It should engage right away when you power it, if it doesn't the clutch is bad.
Now you can crank the engine and leave the clutch hotwired so you can add freon to the system

Good news
Found the problem, did not have the charge hose to the freon can, tight enough to depress the valve in the can tap, got it to charge, btw, there is a relay that can be jumpered to make the compresser run
bad news,
it appears to have a leak, haven't found it yet, no oil around compresser, etc, appears to be a fairly substantial one. a week ago everything looked good, this week, no pressure. Thanks to all that replied, it was appreciated.

[CDJr]

Well, you need to find the leak ASAP, while it still has pressure. If its leaking that fast, it shouldnt be hard to find. Check the connections on the high-pressure side, as they are much more prone to leak. Look for oily areas around every connection, and it may help to use some liquid leak detector or some dishwashing liquid diluted with water. Hope this helps.