ac cycles off and on

Hard to tell without knowing what the high and low side pressures are.

Too little or too much Freon. And other reasons, like high engine or transmission temperature and so on. Check for leaves or other stuff blocking the condenser.

Al

That's how they work. It's normal. It's called CCOT system. They've been that way since 1977.

I also have a problem with my compress kicking on and off. The problem it stays off for long periods of time. I bought a gauge for the freon level and it said that it was over. I didn't put any in. I took it to my mech. and he unpluged the sensor and plugged it back in and the air worked perfect, at least for awhile. I took it back to him and he looked it all over. He said that it was a pound low and added some freon. Then when I would start my truck and turn on the air, freon would expload out the compress. Now after a month, it is starting to not run sometimes. My mech. said that there could be a blockege, or the compressor is going bad. Does anyone have an idea about this? I have a 03 Silverado 5.3......

Can't imagine a truck that is only 4 years old having a bad compressor or blockage. I'd take it to a different mechanic, one who specializes in vehicle AC.

I would take it to a different Mechanic. BUT on my 03 Silverado, the Compressor took a dump on me. My truck was only about 1 year old at the time. I got it replaced under Warranty, but still to this day, I don't know if it's normal? But on Hot days (just happens faster then cooler days) if I just sit in one spot for not very long, it stops being Nice and Cool, and slowly starts warming up more and more until it's almost HOT Air coming out, yet when I start Moving again it cools back down again. Moving as in 30MPH or something, not a slow Crawl. Normally it's not a problem, but when I go to some Event, say the State Fair, and I'm sitting there in LINE waiting for Parking forever it seems like, I end up having to just turn it off as it's getting me even hotter, turn it off and open the windows. Is this Normal?

No, do you have a fan with an electric clutch? My TB did the same thing and the dealer replaced that part and it was much better. Still not as cool as moving but tolerable.

Hide quoted text -

That's not normal.

Damn, my 03 sileverado just started doing the same thing, starts of fairly cold, then gradually after a couple of minutes goes warmer and warmer, then it blows warmer air than outside, I reset the sensor plug and it seems to blow cold again, and then repeats the gradual warm air cycling. The indicator lights on the A/C and inside cab recycle buttons are still lit. Would the system not shut off when it sensed low freon(gas) pressure???. Buddy said it's probably low on freon(or whatever it is in there), which it might be, but that would also indicate a leak. Up until this started, it was blowing cold air just fine....anyone figured this out yet?

Thanks

Phil

An automotive AC system is not a true "closed system" like your house. There are shaft seals on the compressor, and o-rings in many of the connections as there is vibration and flexing in the lines a house system doesn't see, and over time every automotive AC system will loose some refrigerant and need periodical top offs. A 1/4 pound of refrigerant on today's cars can make a major difference in cooling. Be happy you don't have ford's fabulous spring locks(oh but they made me a lot of money)

Whitelightning

FORD?...never owned one never will.

So, I went down my local rad man who does A/C, he said it was either the A/C low presure cycling switch or the compressor coil, the cheaper of which is the switch(on the dryer can), so i picked one up from the gm dealer for 47.64 cad tax in, after a day of running with the A/C on full blast, the problem seems to have cleared.

After which while surfing, i found this document duh?????

"Some customers may comment that the A/C system is intermittently inoperative or blows warm air. CAUSE: An intermittent inoperative (open) A/C low pressure cycling switch may be the cause. This is an intermittent condition, and temperatures may play a critical role if the vehicle is in the failed mode or operating as designed."

PN# 89040362 SWITCH

I have read that on some GM's there is also some control part in the dash or a computer module somewhere that goes bad and causes similar symptoms. There was a TSB on it.