intermittent A/C problem 2001 4.3L 4x4

hello all, i've looked everywhere for the solution to this problem to no avail, which is:
when i turn on the A/C, it sometimes blows out cold air, and sometimes warm air. i checked the pressure at the A/C service port, and it read 45, which is in the full range. what else should i do? am i supposed to add more r134a refrigerant although the gauge reads full? i don't want to screw up the a/c in the middle of summer. thank you all in advance for your suggestions, it is muggy and nasty here in the Big Apple.

hello all, i've looked everywhere for the solution to this problem to no avail, which is:
when i turn on the A/C, it sometimes blows out cold air, and sometimes warm air. i checked the pressure at the A/C service port, and it read 45, which is in the full range. what else should i do? am i supposed to add more r134a refrigerant although the gauge reads full? i don't want to screw up the a/c in the middle of summer. thank you all in advance for your suggestions, it is muggy and nasty here in the Big Apple.

HI, had the same problem. I'm not a mechanic either. There is a switch on the ac unit (ac compressor switch), costs like $20 or something and it has a cable going into it. The switch bolts onto something like a beer can. Easy do it yourself fix. Told the chevy guy the problem and he tapped the switch to make it work, basically told me how to fix, all this was done "under the table" while fixing a different problem. Good Luck

i'll get the A/C compressor switch replaced as advised.

Sounds like you are low on R134A.

Go to autozone and get one of the Measure and Charge Top up kits from Interdynamics and remember to fill with the AC on MAX and the fan on full blast.

They come with a gauge that will tell you if you are in the right range.

Remember to get a kit with compressor oil in it. When you install more R134a, you also need to install more oil with it.

Thank you BlazerLT; in fact I got the kit last week and the gauge reading at the ac service port was around 45, which is full, am i right?? this is why i am a bit puzzled as to the cause of this problem.. i haven't charged the system yet b/c i was under the impression that it's full and something else is causing the problem.

Did you test the pressure with the temperature to cold, AC on MAX and the fan on full?

Yup, i followed the instructions on the kit.

What kit did you get exactly?

Interdynamics EZ-Chill, Model #RKR-7

I know you said that you had it set to max a/c when you tested it, but was the compressor running?
Does the compressor stay on or does it cycle? Is the compressor running at the times when the vents are blowing warm air?

The AC service port you should be using is on the side of the tall metal accumulator.

You sure you are using that connection?

BlazerLT: yup, i'm using the one on the accumulator, it's cylindrical and metal coated, right?

Blazee: there is a torrential downpour here at the moment, so i'll run the engine and ac tomorrow to test the compressor. i'll post the results.

ok, thank you both...

thank you all for your help. BlazerLT you're right, i checked the psi this morning FULL MAX, engine ON, and it only read 25, added 3 cans of R134A, brought the pressure up to 45 psi, and it's been blowing ice cold ever since without a problem.

thank you all for your help. BlazerLT you're right, i checked the psi this morning FULL MAX, engine ON, and it only read 25, added 3 cans of R134A, brought the pressure up to 45 psi, and it's been blowing ice cold ever since without a problem.

http://www.yourethemannowdog.com/ ;)