air cond. question

Hi everyone, I have a 90' lumina euro and I was wanting to get the a/c going in it. The previous owners I purchased it from said the a/c needed a charge. I recently bought some freon and put it in and I figured the compressor would kick on but it did not. I often heard that you need to "JUMP" the compressor to get it initially going, once it does everything should work ok. Is this correct? And if so how do I go about doing it? Any replies would be greatly appreciated!!

Hi everyone, I have a 90' lumina euro and I was wanting to get the a/c going in it. The previous owners I purchased it from said the a/c needed a charge. I recently bought some freon and put it in and I figured the compressor would kick on but it did not. I often heard that you need to "JUMP" the compressor to get it initially going, once it does everything should work ok. Is this correct? And if so how do I go about doing it? Any replies would be greatly appreciated!!

You jump the wiring at the low pressure switch, which is usually right next to the receiver on the cold side. The two wire plug can be shunted with a paper clip, and the compressor will start.

I don't reccomend it though, unless it refuses to start after putting some charge. Most will start up almost right away as the freon goes in. Running cold water from a hose across the condensor (in front of the radiator) will lower system pressure and allow it to accept the charge faster, keeping it engaged longer while charging.

I have kind of the same issues with my 95 lumina. I tried to charge it with one of those kits from Auto Zone, and it wouldn't take any of the refrigerant. The compressor won't engage. Should I try to "jump" the compressor like you explained, or is there something else that I can try that is less expensive than getting a different compressor. Oh yeah, I also switched out the relay, so I know that that is not the problem.

You can, it will at least tell you if the compressor works. Then you can see if it seems to be functioning (lines cooling, sweating up) and if you have a gauge on that refill kit, check the pressure.

You should see about 30-35 psi on the low pressure side of the system (system charged) with the compressor running. If any higher, don't try to charge it...it's too high, something's wrong. When your charge first starts going in, it'll shoot up to around 90 psi then fall back down as it circulates.

On my '97, the receiver is under the airbox, and though I never paid any attention, I'd assume the low pressure switch is near there.

Thank you!!!

Folks, a word of warning to those who are buying the R-134 "kits" at your local parts stores. Make sure that the cans of freon you're putting in do not ALL have the oil charge. I found out the hard way with a Dodge minivan that also runs 134. What is sold in most auto stores are the "all in one" products which include a 2 oz. oil charge with each can of freon. Your entire system only takes 2 oz's of oil, so if you put all 3 cans (typically found in the kits) you're overcharging your system with oil. That leads to very bad problems with the compressor and evaporator as the excess oil collects in both areas.
Make sure if you're buying over the counter kits that only 1 oil charge is being applied. Hopefully future readers will save themselves the 200 dollars that THIS lesson cost me. :)

Folks, a word of warning to those who are buying the R-134 "kits" at your local parts stores. Make sure that the cans of freon you're putting in do not ALL have the oil charge. I found out the hard way with a Dodge minivan that also runs 134. What is sold in most auto stores are the "all in one" products which include a 2 oz. oil charge with each can of freon. Your entire system only takes 2 oz's of oil, so if you put all 3 cans (typically found in the kits) you're overcharging your system with oil. That leads to very bad problems with the compressor and evaporator as the excess oil collects in both areas.
Make sure if you're buying over the counter kits that only 1 oil charge is being applied. Hopefully future readers will save themselves the 200 dollars that THIS lesson cost me. :)

Good advice, but I'll do you one better...if you are just recharging, don't add ANY oil charge. The only time your system should need oil added is in the event of a major component replacement (comressor, reciever, condensor, etc) and even then you have to very careful not to go overboard.

I forgot...the 134a "retro fit" kits include an oil conditioner charge that has to go in, it conditions the current oil in the system so it (hopefully) won't coagulate in the system with the new 134a in there.

You have to add this, but that is also assuming that you follow the rest of the directions explicitly, including a proper evacuation of the system (which draws out a small amount of oil as well) before adding the new stuff.

Lotta people just blow the whole kit in there, and end up with a double problem of too much oil plus air present, which causes high pressure and blockage issues. They will work, but will cut out under certain conditions, and are prone to compressor and hose failure due to high pressure events stemming from all the contamination.