Mechanics

CHEVY AC NOT WORKING

1999 Chevrolet Silverado

Air Conditioning problem
1999 Chevy Silverado V8 Four Wheel Drive Automatic 195000 miles

About a month ago, my compressor went out. I had it and the accumulator replaced. It cooled for a couple of weeks and now it will only cool for about five minutes. The compressor seams to not be turning on. I thought it was the clutch cycling switch on the accumulator, because I could remove the wiring harness and install a jumper and it would kick on. So I replaced the switch and now the compressor will not switch on. Once again, I tried the jumper, still nothing. I have a low pressure gauge and it is showing a reading of 65. Any answers would be greatly appreciated
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Btuggle
August 9, 2010.




Take it back to where you had it repaired as it's not been a long time. It sounds as if they didn't do something right like didn't evacuate the system like it should have been and your unit is freezing up. It cools then warms then if you continue will cool again. Or there is a blockage in the orfice due to compressor failure, which means theys should have done a freon cleansing before replacing the part as little particles get int eh system and block the orfice.

Hmac300
Aug 9, 2010.
They say they flushed the system out, but I will take it back to them. One thing I did notice yesterday when the compressor was kicking on and off, the gauge readings went from 35 to 65+ as it would kick on and off. When it quit working, the pressure reading remained at about 65.

Thanks for your help.
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Tiny
Btuggle
Aug 9, 2010.
35 is abotu right on the low side depending on the temperature outside when the compressor is on. But it still shouldn't stop cooling like you've said. There is definitely something wrong with it. I still thinkit's got a freezing up condition but that would take evacuate and recharge on the system and probably change the acumalator to keep it dry.

Hmac300
Aug 9, 2010.
I will not be able to take it back to the repair shop where I had the compressor and dryer replaced till next week. However, when I got home from work yesterday I decided I would evealuate it some more and discovered what felt like air blowing from evaporator tube where it connects at the entry to the cab. Could this leak be the possible problem?

Tiny
Btuggle
Aug 13, 2010.
Sorry about being late with this as i've been away. The air blowing out is just air and unless it is a quite a bit which I doubt, it isn't causing the problem. That can be taken care of with what mechanics call dum-dum. From what you describe it still seems to me to be " freezing up" I have to beleive that it's the orfice is being blocked once in a while causing t eh problem. You migh tmention this to them, but hard telling what they will say. The orfice has a filter on it and it may be plugging then breaking loose and blocking again. I would take a look at it anyhow then try a pump down then a freon sweep and pump down again before refilling the system. That way the moisture that may have built up in the system should all be gone.

Hmac300
Aug 16, 2010.
Sorry, I know it has been a while since I have been on here. I finally took my truck back to the shop that replaced the compressor. System was full of freon and everything checked out except that non of the switches (high or low pressure) are getting any power to the them. The mechanic told me that it could be the circuit board in the dash. He is supposed to find a wiring diagram so tha we can check it out. O you have any ideas of what it could be? Thanks!

Tiny
Btuggle
Oct 14, 2010.
I am taking it that this is a 5.3L and you have the basic a/c. In the underhood bec there are fuses and a relay that go to the compressor. these could be a blown fuse, a relay not working or not getting a good connection there as well as the computer.... i'm sending the basic wire diagram along on here. I think you should be able to enlarge it , if not print it for sure and then enlarge it...


http://www.2carpros.com/forum/automotive_pictures/406719_ac_1999_1.jpg


Hmac300
Oct 14, 2010.
Thank you so much, will check out this weekend.

Tiny
Btuggle
Oct 15, 2010.

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