QuestionThe A/C on my 95 Monte Carlo just went out today. Blowing nothing but hot air. I bought a recharge kit, started my car & turned the A/C on high, then connected the kit. The pressure gauge shot up into the red. I tested it on my 04 4Runner to make sure I did it right & that reads correctly. Is there a way to release some pressure or is something else going on here? Thanks for your help.
AnswerRich,
Before you go releasing pressure you don't need to...
There is definately something else going on. The reason your gauge shot up into the red was because your compressor was not engaged. Without the compressor there to create a high side and a low side the pressure is equalized between the two. On an average day it will equalize out at about 100-140psig. Your gauge is only designed to read about 30-50 as in the green. Nothing is wrong there.
The first thing I want you to do is look at your fuses.
You should have two of them for your A/C. One 15A or so inside the cab fuse box, and another in the underhood fuse box. (25-40A) If both of these are good...
The next check I want you to make is your compressor clutch relay. This is in the engine compartment "fuse box". Turn your key to run (engine off) and your a/c switch on. Unplug this relay from the socket. Plug it back in, as you do listen and feel for a soft "click" from the relay. Do you hear it? Did your compressor clutch engage (loud snap)
If you felt the relay click, and the clutch did not engage... check the compressor ground. Make certain it is tight and has no corrosion built up on it.
If the relay did not click... with a small jumper wire jump the contacts in the socket from the socket with the dark green wire connected to it to the connector with the dark green/white strip connected to it. If it helps you at all... the schematic has them labeled as E6 and E8. Not sure if you will see something on your side that matches up with that or not.
Did your clutch engage when you jumped it? If so... replace your relay. If not... leave the contacts jumped and move to your low pressure switch. This is a switch that is located on your low side line. The schematic says that you have 3 wires coming from it. A Gray, Black, and Red with a black stripe. Disconnect the wiring harness plug from the switch. Inside the harness plug jump the Red with black stripe to the black wire. Did your clutch engage? Yes? Well, being that your gauge says you have a charge in the system, it is a safe bet that your pressure switch is bad.
No? The only thing left to check is your Power Control Module, and I won't tell you how to do that simply because if I tell you and you make a slight mistake, it could fry it. I would recommend at this point you take it to a reputable shop and have it diagnosed.
But typically, the fault will lie in the fuse, relay, or low pressure switch. It is rare that I see a PCM that goes bad in the A/C controls. Rare, but it happens. Also, remember that if a fuse blew, something caused a large enough drain somewhere in the system to cause it to blow.
I hope this helps you out a little. If I can do anything more, now or in the future, do not hesitate to ask. Thank you for the question and good luck in everything.
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