A/C not working in the rear, not cold in front, cool at best. Hook up a gauge to the low pressure side and it reads in the zone on the gauge that says it has enough coolant. Low but in the good zone. I tried to add more coolant to bring it higher in the good zone but it seems like the system isn't accepting more coolant.
Compressor seems to be running. But not sure. From time to time I hear a strang pinging sound from the dashboard, almost every time I put the rear a/c on I hear a pinging sound that almost drowns out the radio. Coming from the right rear where the a/c unit is in the rear. Not sure if related to issue. But when the sound started the a/c stopped.
Was the compressor running when you had the gage attached? The pressure on the low side (where you had the gage attached) should be around 30psi (good zone) with the engine running and the A/C turned on and the compressor clutch engaged. When the compressor is off, the pressure on the low side should come back to somewhere near 100 psi. SO, if you checked the pressure with the compressor not engaged and read thirty psi, then the system is very low. Also, the system will not accept much freon from the can if the compressor is not running, and the low pressure clutch cycling switch will keep the compressor from running if the system is very low on refrigerant. Sometimes you have to put a jumper wire in the harness connector to the pressure switch for the compressor to come on so it will begin accepting refrigerant from the can. Once there is enough Freon in the system you can remove the jumper wire and plug the switch back in. Then the compressor should continue to run long enough for you to add more if necessary. It is a bit of guesswork to try and charge up or diagnose an A/C system without a propper set of A/C gages hooked up so that you can see both the high side and low side pressures.
I have no Idea what the noise could be. I would have to hear it to even give a guess, other than maybe the blower motor fan is hitting something.
If it is a hissing noise then it might be the freon passing through the expansion valve or orifice tube.
"What should I check next?" You should check to make sure the compressor clutch is engaged and you should check both the high side and low side pressure readings with the compressor running. That would be the first step towards diagnosing the problem, unless you can figure out what is making that noise first.
I have a bit more info and thanks for your help so far Kevin or anyone reading this.
Yes the compressor is turning when I push the AC botton on.
It stays on until I push the AC botton off.
When I attach the pressure gauge on the low side it reads over 25 and just below 30.
There is no condensation on any of the AC pipes.
I'm very handy but I'm not trying to fix the problem. My goal is to educate myself and not to get ripped off when I go to get my AC repaired. Can I assume it is not a leak or the compressor? If it is not the compressor or a leak what can it be? My friend seems to think that if the compressor is kicking in that it should be functioning.
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