AC blows cold sometimes and Hot sometimes

Hey there. When you say that the compressor cycles on and then off, does it cycle back on? Most AC compressors have a clutch and they are designed to cycle on, off, on, off, etc. Also, you say you're trying to charge the freon but do you know how much freon is actually in the system already? Best way to recharge the ac system is to perform an evacuation of all the freon using an AC machine and then performing a vacuum on the system. Monitor the gauges to check if you start to lose your vacuum which would indicate you have a leak somewhere. If the vacuum remains the same, then you recharge the system with the appropriate amount thats located on the AC placard somewhere in your engine bay.

Just to add to this one that is not a cycling compressor most GM cars are not. The gauge cannot tell you how much charge is in the system. That is why it is best to charge a empty system so you know you have the correct amount of charge. Or what the professionals use a AC machine so they can evacuate and weigh what comes out. So they no how much charge was in the system to know if it was fully charged over charged under charged etc. Also reasons for compressor cycling too high of pressure built so compressor is shut off as well as too little of pressure can shut off as well. Also not enough air being pulled through the radiator and AC condenser do to sand debris fan not working etc.

Thanks saturntech9 for clarifying if his compressor was a cycling compressor or not. All cars I have worked on so far have a clutch. Everything else is spot on as well. Thanks for reassuring.

They all have a clutch or a bypass valve they use instead of a clutch to bypass the pressure to do the same thing a clutch does. You are welcome anytime we are here to work as a team.

Alright, keep us posted.

So while driving down the road it blows cold, but when you stop moving it blows. Hot?

So is your radiator fan/condenser fan turning on with the AC?

Yes see if the radiator fan/condenser fan turns on with the AC? Does your radiator fan turn on when the car warms up?

I have seen strange things with radiator fans not working and people only complaining about the AC only working when driving.

Keep me posted.

Sounds like the radiator fan is not working properly. With the AC on at idle try smacking the fan motor see if the fan starts spinning?