A/C problem

I am having a A/C problem on a 1996 chevy suburban. The A/C is not blowing cold air and compressor is not engaging. I First checked the pressure on low side which read zero. I then charged the system with
the ac on full blast. The ressure is at 35 with hardly any of the can going in so I knew the compressor was not engaging. I then checked the accumulator by passenger side and it gets voltage when I hit the AC button. I then checked the wire that leads to front of AC compressor by the pully and I dont see any volatage going to there with everything on. There is also a some wires going to the backside of the compressor but I did not check those yet. Any ideas on what to check to see if I can get the AC clutch to engage. - Thanks for any advice
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On Thu, 2 Apr 2009 20:17:55 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

Damn, that's a good question. :-) It is entirely possible that your AC system is full of lubricant and not refrigerant. That can happen if the AC system was not properly drained of lubricant in the past when new refrigerant was added. The cans one buys at auto parts stores contain both lubricant and gas, and as it says on the label the lubricant inside the automobile's AC system often has to be pumped out since it isn't usually drained via gravity.
The AC system, as it sounds like you already know, has a pressure switch that monitors the gas pressure: if the gas pressure is too low, the pump will not turn on--- it is as if there is no electricity going to it at all. If you have too much lubricant in the system, you will not be able to fill it with gas and the pressure switch will stay "off."
Then again I could be 100% wrong.
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wrote:

If the low side is reading 0 PSI then I suspect that the system has leaked down and lost it's refrigerant. If that is the case you need to connect a vacuum pump and pull a negative pressure on the system in order to refill it with the proper refrigerant. You should also add a can of refrigerant dye to the system and look for leaks since the system leaked down. Those "auto store" refill kits are pretty much worthless when a system has leaked down to 0 pressure. You can force the compressor to turn on by momentarily touching a jumper wire across the contacts of the connector that plugs into the pressure switch. A good set of proper AC gages, vacuum pump, refrigerant, and know-how make this job a lot easier and safer. I have about 550 bux tied up in just a set of gages and vacuum pump and more yet for Temperature /pressure differential charts and certification to be able to buy refrigerant. My advice is to take the truck to a shop with a rep for having a good AC tech and get it done right. You have to decide if the cost is worth it or not. At this point it sound like you are over your head, no offense intended.
Regards JR
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Quite seriously You know just enough to be DANGEROUS! when it comes to AC Your Suburban needs the LEAK FIXED, then evacuated and then FULLY Charged with R134a
THEN you will have a functioning AC system. Buy walfart cans and putting them in is DANGEROUS and wasteful! Do you pour Jack Daniels into a cracked and leaking glass? It wastes good Whiskey!

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