First of all, I have read through all of the A/C sticky post and was unable to find an answer. I recently found that my A/C compressor would not turn on and so the first thing I did was check all my electrical connections. I have power on both sides of the relay with the A/C on, but neither of the grounds will create a complete circuit. I tested the ground on the connection at the compressor and t tested out fine. All that leaves me with now is a problem with the cars computer as it's the only wire that doesn't check out properly. Is there a chance that the computer somehow wont allow the low-end circuit in the relay to complete and thus complete the high end circuit to run the compressor? Anyone experience similar problems?

will the compresor cluch engage if you jump the relay?I'm not exactly sure how cavs are wired but that may bypass the computer if the relay is energized by the computer. You may have a bad relay. Also you need to consider that if one of you pressure sensors are bad and reading that the system is low the compressor wil not cycle. Also you system could be just low.


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Yeah, we jumped the relay, just directly connecting the high end circuit and that gives me power at the compressor connector. I never did plug it back in to the compressor and jump it, but I do have power there. I thought it might be the relay too, but a brand new one made no difference. I know for a fact that the system is low as it's had a bit of work done, replacing the evaporator, and was never properly charged up again. That's the problem, I can't charge the system without my compressor running. I'm pretty sure it is the pressure sensor on the PCM, as that's the only factor I haven't tested yet. If my Haynes manual is correct, which it rarely is, the wiring diagram shows an orange, hot always wire coming into the relay and going out as a green wire to the compressor. A pink wire then comes in and carries the signal from the HVAC controls for A/C on, which then runs out as a green w/ stripe wire to the PCM. Seems to me that the PCM isn't allowing the signal circuit to ground and complete which then prevents the larger compressor circuit from completing through the relay. Sound about right?

Matt Webb wrote: I know for a fact that the system is low as it's had a bit of work done, replacing the evaporator, and was never properly charged up again. That's the problem, I can't charge the system without my compressor running.

There should be a switch in the compressor that won't allow the compressor to come on uless it has enough refrigerant in the system. It should come on when you start to fill the system. Does the compressor engage at all? Normally they click on and off when the system is low.

josh

No, I can't get the compressor to engage at all, even when attempting to fill the system. I think I may try jumping the relay to start the compressor, try to recharge the system at that point and see what it does for me. Any and all suggestion in the meantime would be greatly appreciated.

Jump the low pressure sensor. This should tell the comp that the system has enough refrigerant to cycle.


My Car

Well, I jumped the relay just long enough to get a small amount of refridgerant in, put the relay back in and it ran fine on it's own. So, I was able to get the system recharged, compressor works fine, now I just need to search for leaks. Thanks alot guys.

So you jumped the relay at the main fuse block in the engine compartment? I thought there was a spot along the compressor line or something where the cutoff switch was located... I have a 95, btw, but I think our setups are the same.

Any help would be greatly appreciated.

Thx.






L8r...
___________
. . . . jb . . . .
...Son Fire!


*** Need some 1995 Cavalier parts ???
*** FOR SALE: doors, windows, interior, engine parts, fenders, etc. -- email me

Yeah, just that main fuse block there inside the engine bay, jumped the relay to engage the compressor clutch and help it just long enough to get a small charge in the system. That was enough then to "tickle" the computer and allow the compressor to run on it's own like it should. Now are you talking about an electrical cutoff or a cutoff in the pressure lines? As far as I can tell the hot wire just runs from the high side of the relay back into some wire loom and then right to the compressor. The relay itself would be the only kind of cutoff in there.

I thought I read somewhere about a low pressure switch that was located along the actual lines themselves that wouldn't allow the compressor to engage if the refrigerant pressure was too low... Must have been thinking of something else.

I'll try this out tonight and let you know how it goes for me. Thx.





L8r...
___________
. . . . jb . . . .
...Son Fire!


*** Need some 1995 Cavalier parts ???
*** FOR SALE: doors, windows, interior, engine parts, fenders, etc. -- email me

Well, I jumped the relay in the fusebox and I was able to get a charge into the system (enough to get the compressor to work WITH the relay installed) so I could pump in some refrigerant. It took forever for the refrigerant to get into the system, however. I think shaking the can and then pressing its button worked best (on my wife's car). I'm going to check the pressure in a few dayz and see where I stand, and perhaps add a bit more to my Fire (it is still on the low side).

Thanks to all for your help ... as always!





L8r...
___________
. . . . jb . . . .
...Son Fire!


*** Need some 1995 Cavalier parts ???
*** FOR SALE: doors, windows, interior, engine parts, fenders, etc. -- email me

Does anyone know where that pressure switch is located? I was going to jump the leads on that pressure switch to get the pump going.. but I guess the relay method would work fine... which leads did you short out on the relay? or is there only two?

dude, i have had so much trouble with my a/c i gave up. First, my discharge and suction line had a leak, 80 bucks for that and a good 25 bucks for chemicals to refill the system. Then I had a leak in one of my high pressure side lines. 20 bucks for the aluminum line, 30 more bucks for the chemicals. (bought a can of stop leak that time) and it stayed charged for a few days. The thing was so cold, it would almost freeze you out of the car. 2 days later, it was empty again. I have no clue. Im very angry at my car right now! Its broken my wallet!


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Is it possible you have a leak in the front seal of the compressor. That's usually where mine start to leak first. Also the hardest to fix.

well... I figured out which lead to short out.. thanks for the help anyway. Wr got it charged back up.. costs us under 40bux.

Anyone looking to recharge their system... I bought 2 cans of R12a refrigerant for 12.99 each over the counter. You do not need a license for R12a. I also bought a can of sealer for 20bux. I live in canada and our laws for refrigerant are alot more strict than american laws.. so I don't see w hy you guys can't do the same to save.