96 Tahoe Ac Question...

First off, I'd like to say hello and thanks to the people who've provided insight on all the other posts I've been reading on here for a while. Definately has saved me some headaches.

This is my first post and hopefully you guys can help me out....

Trying to troubleshoot the AC. This is a vehicle I recently bought and the AC wasn't working when I got it. I'm not a seasoned AC guy and don't really no much about how the system itself functions. I do know that the compressor would not engage at all. After checking all the fuses and testing for proper voltage at various test points I finally found that jumping the switch at the accumulator engages the compressor. So I thought, thats easy, I'll go grab the $20 switch an be done. I've replaced the switch and still no go. So I assume the system itself is not functioning correctly therefore not "flipping" the switch. So what is the next thing to check......

Any help is greatly appreciated....


I just found this thread: http://www.automotiveforums.com/vbulletin/showthread.php?t=703268&highlight=Accumulator
but it looks like its fizzled out....


Also I'm at 35psi on the low side...

You are low on R134A. The preasure switch see no preasure and shuts off the compressor so you do not burn it out.

Appreciate the quick reply...

I was showing 35psi on the low side, I just went out and managed to get it around 40 psi. and it still doesn't come on. I was reading a post earlier that said it should trigger the switch at around 28psi. Could the accumulator be bad or be clogged somewhere?? or could the system have a problem elsewhere in the line. I would assume since it is a recirculating system that the accumulator relies on another process to be functioning correctly. If I new more about how the system "flows" I guess it would be easier to understand....

If you have a set of guages you should have about 60# on both sides with the engine off. If not you are low on R134A. Start the engine and turn on A/C. You should have about 35# low and 200# high.

Appreciate the info taillight....

I found a thread on another forum talking about not to trust the guages on the R134 refills and that turned out to be it. I was thiinking I had enough pressure in the system but didn't. Lesson Learned.....

thanks again....