Compressor Problem
Thread Starter
Racer
Joined: Aug 2002
Posts: 305
Likes: 0
From: Mo
Compressor Problem
I changed my freon to R134 for my '92 coupe. The compressor will not engage. Preliminary tesing shows no signal from a computer to engage the compressor. My question is which computer engages the compressor when the air conditioning is activated. Can this computer be purchased online. I prefer to fix this problem myself if possible and not take to a Chevy ($$) dealer for repair. Any input would be greatly apprceiated Thanks Gary
Thread Starter
Racer
Joined: Aug 2002
Posts: 305
Likes: 0
From: Mo
Yes thats the first thing that was checked thanks Gary Whoa !! let me back up I did checked the fuse box. Pressure swithches you've lost me. What and were are they and how do I check them. Thanks again Gary
Last edited by oldtimer; May 4, 2011 at 01:28 PM.
Racer
Joined: Jun 2010
Posts: 290
Likes: 5
From: Winona MN
I'm not sure of the exact locations but follow the lines and you will find them. On my 88 they are back by the heater box where the lines connect to the ac evaporator. There is also a separate fuse for the AC/Heater controller.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
If this is otp 68 elect a/c control the BCM has to get a clear signal from this single circuit that is a "loop" past the compressor clutch, hi & low press switch and a cycling switch sometimes. The BCM manages this by completing the ground path.
If you just went to 134a, you may need to jump the low pressure switch to "trick" the system to get the compressor to come on. Do so CAREFULLY so you do not burn up the compressor with inadequate pressures. Use gauges. It takes less 134a to be efficient. Add oil charge FIRST.
The compressor will not engage unless there is a min pressure, or the switch is jumped. It takes about 1 to 1.5 lbs of 134a to have enough charge for the low pressure switch to operate without the jumper.
You will also have to adjust the low pressure switch for 134a.
