Air conditioning blowing warm
2001 Monte Carlo LS
Previous owner said car was wrecked by hitting deer and repaired. He feared the compressor may be bad, not replaced, but he wasn't sure.

Okay, I've searched and I've done all the troubleshooting I can do so far without taking it to a shop. This is more of a share your guidance/experience.

1) Can you buy a fused jumper for testing purposes or is it something you have to make?

2) A/C symptoms: I followed the Haynes manual on basic driveway troubleshooting. No fuses blown. The compressor clutch doesn't appear to be engaging at all, but I can't hook it up directly because I don't have #1. So I tried shorting the wires on the the low pressure sensor. Still nothing. What I did notice though that when I pulled the low pressure sensor off, the engine slowed from idling at 900/1000 rpm to about 600/700 rpm's. Put it back on and the engine cycled back up to 900/1000. Then i realized the same thing happens when I turn the A/C on and off from the regular switches.

So, I'm deducing that the engine will cycle up to 1000 rpms when the A/C is turned on to compensate for the extra drag, and that my refrigerant pressure is fine since the A/C is trying to work. And when I simulate low pressure by removing the low pressure sensor, the system kicks off. Following this, then my compressor is probably bad since I have good pressure (no leaks), but I still blow warm air.

Is this a fair deduction or am I just out in left field somewhere? Thanks in advance.

 

Update to #1 - a nice tech at pep boys pointed out that a circuit tester to verify power at the connector accomplishes the same thing as putting a jumper on. If you have power, then it's the part that's bad. a few bucks for a tester and I feel better then chancing melting an improperly made jumper.

 

Update to #2

With engine running and A/C cranked ..... I have power to the compressor. (I shut down the car) To just make sure, I can turn the inner core of the compressor, but it's not turning/clicking at all when the system is on. I think I need a new one. Darn.

 

Pull the ac comp clutch relay and jumper 87 and 30 with a bent up cotter pin or a piece of steel wire. It won't hurt anything if the clutch is working it will be forced to engage. If that works the relay could be no good so switch it with something less important to see if it works normally. If the compressor makes a lot of noise when it's jumpered it probably low on R134a freon, and oil sor shut it off. The accident probably wiped out the condenser and may not be fixed properly or leaks from a fitting.

 

You need to put a set of gauges on the car to see if you have any pressure. I'm betting that if you have power at the compressor but it doesn't kick on, the system is probably too low to kick the compressor on or its empty. Its possible that the condensor is damaged as Justin Knight has suggested or that they replaced some part of the AC system and did not recharge the system. The clutch could also be bad or out of adjustment. The correct clutch gap on most vehicles is the thickness of a business card. You could try tapping on the clutch with the vehicle running to see if it engages.

If its empty you can try charging in some R134 with dye in it and see where you have a leak. Some vehicles also set a code that is stored in the BCM if the system becomes to low on refrigerant so that you don't damage the compressor. My 92 Cavalier does this. Let us know what you find out.

Wayne

 

Well, I did as both of you suggested. I pulled the relay and jumpered 87-30 and it didn't so much as 'click'. It's tight around the compressor (and my dumb A$$ almost stuck my hand in the serpentine belt the other day) so I took a large screw driver and tapped on the clutch face, still with no reaction. AND just to cover my bases, when the clutch engages, the whole inner core of the compressor wheel will spin, correct? As I said earlier the inner core spins freely. Another additional fact I didn't include is that the belt side of the engine has ALOT of oil/road build up on it from god-only-knows what kind of issues (hopefully past issues), and the compressor has been coated nicely in it. It wouldn't surprise me if the innards are all gummed up and unusable.

And with your other inputs due to the wreck, I'm still leaning toward some professional attention and new parts are probably better investments in the long run. But I'll pursue any other recommendations ya got, because if it is the compressor, the A/C is going down to the bottom of the list for a while. I have intake leaks and other affordable items to address first. I'll do any recommended testing, though, if only for the experience.

Thanks again.

 

Additional note: (one of these days, I'll compile all my stuff into one posting)
The previous owner had bought a recharge kit that has the psi gauge on it. So I put it on just for grins and it is reading approximately 46 PSI on the low side which the bottle says is about right for this temperature. This measurement was taken with car turned off and running w/ A/C on (no change). Would the compressor not running make a false reading like this or can you make a fair judgement that there aren't any leaks?

 

It's definatly low on charge the low side reading should be around 30-10 psi running and when the car engine is off the high and low side will eventually equalize and be the same +- 2 psi. High side running should be over 200psi on a hot day will full charge but I'm positive yours is nearly empty. 42psi is low enough that the pressure switch should disable the clutch from engaging. And if it is engaging still stop trying to run it because it's at the most damaging point to a compressor. Not enough cooling or pag oil anymore.

Seek professional diagnostics and repair, the repair in a can will not fix your problem and never use a injected sealer ever.

 

Gotchya! Thanks for all your help. The 'recharge kit' mentioned does have leak sealer incorporated, so I'm pretty sure its got that stuff in it's pipes somewhere (not by my hand, the previous owner). I've read enough on these forums to avoid any canned-fixes.

Once again, thanks to all.... this goes to the bottom of the repair list for now.