Here is what you can do to save yourself some $ and test it out.
Go to your local department store like a Wal-Mart, K-Mart, or Meijer and see if they have the retro fit recharge kits. Try to do the retro fit procedure and recharge the A/C yourself. The local Meijers was selling them for less than $20 a kit.
This way you can see if it is just low on freon. Also, if it does work, then slowly gets hot again, you more than likely have a leak.
If all of this fails, then you will have to go the next step and have a technician check it out for you.
This way, if it does work, you would not have spent the standard hrly rates to have it checked out, etc.
Wait wait, blows hot air? What causes it? Is it just constantly blowing hot air? Ok, it might not be your compressor at all, and it might not even be your refrigerant. Do this:
1) pop your hood
2) At the front of your car is your windshield wiper fluid reservoir. Lift it out.
3) Underneath it is the reciever/dryer. There's a little glass port on top if it, so you can sight if you have R12 in there or not *look for bubbles* But the main thing IS...
There are two pipes going in/out of the reciever/dryer. One is fat *low side* and one is thin *high side* Touch the low side; it should be cold. The high side should be hot. If not; you have a compressor/leak/refrigerant problem. Actually, you can touch the fat pipe coming out of the compressor itself if you want; *any fat pipes you see are all low side, any skinny pipes are high side* all high side should be relatively hot, any fat pipes are relatively cold. If they're the right temps, then you've got a problem in the dash; the blend doors, or maybe your heater core. Post back.
I had to rush off. I did not mention to check this out too!
When you push the AC button on, does your engine kick down as if it's under load, then the idle kicks back up? If so, then it wouldn't be the compressor. If the compressor does not kick in and present a load on the engine, then it is possible that the compressor has gone out.
Now, if it does kick in, then follow the different step Lee756 and I posted.
Just pop the hood and look down at the compressor. If the clutch is engaged when the A/C is on and it spins, it's highly doubtful the compressor has gone bad. The only real way to diagnose the system perfectly accurately is to get pressure readings on the high/low sides, but getting pressure readings usually means being at the mechanic already getting your A/C fixed; that is unless you have friends that happen to have manifold gauges lying around.
The compressor clutch CLICKS when it engages. Listen for the sound to tell you that it engaged properly.
Did you try the hot pipe/cold pipe test? If you still think it's your compressor, (it might be since you said you didn't feel a load) try lifting the car *at a community college or something* and look at the compressor clutch from underneath. If it spins freely when your A/C is turned on, it has gone bad. If it engages when you flip on the A/C, the cluctch is ok, and the compressor [probably] is too. Try the touch test.
I noticed that occasionally my car was blowing hot air as well. But then I read somewhere to check the fan switch. Sure enough, it would occasionally turn off the A/C (you can look at the light on the console to verify this) at the highest setting but then turn back on if I lowered it to #3 vs #4.
If this is happening with your car then it is my understanding that a replacement fan switch will cure your issue.
It's certainly cheaper than an A/C compressor and it's easy to check.
It sound like you have a refigerant leak. Ask your mechanic if they have a freon sniffer. If so have them inspect the entire system to see if they can find the leak. One tell tail sign of a freon leak is a thick stickey oil coming from a refrigerent line or possibibly the condesor.
Another thing is; I wouldn't suggest converting an R-12 system to a R-134A. This might be the cheepest way out but your A/C wont work so well and you can never switch it back.
It can't be a leak because he already had his pressures checked. If the pressures are fine, it has to be an electrical problem or a blend door problem of some kind. Maybe even heater core problems, but that's highly unlikely.
R-134a works just as well as R-12, provided the system is retrofitted PROPERLY. And I've heard of people switching back, but they only did it because the R-134a kept leaking out of the system. R-12 = large particles. R-134a = small particles easily leak out of the system if it wasn't originally designed for R134.
Well it was bad! Good news and bad news! Compressor was leaking--took a look at evap core and it was shot also--Local infiniti dealer and after market shops were outrageous on prices. Took a lead from this forum and call Scottsdale infiiniti and they gave me fantastic prices on needed parts--saved me a bunch of money--Check them out if you have not done so. These guys will work with you on price
Well, Got the Thermal Expansion Valve finally and replaced--We go cold air again! I cannot tell whether I was getting screwed because I bought my parts from Scottsdale or just a bad stroke of luck--I am still way under the dealer cost by 7-800 bucks.
Any way if nothing else maybe this thread will help others. Overall this site continues to save me big bucks!
Well its been a year and now A/C not working again. It worked cold as a freezer at lunch time. Then after work it did not. The A/C switch button does not illuminate--all other a/c-heat control buttons work--Compressor does not come on.
The only weird thing is my battery died today and I had to buy a new one--
Any ideas here? HELP!! I bought a new infiniti compressor a year ago --new expansion valve--condensor--what else can go wrong???