A/C cycling between warm and cold air.
 

Hi, my A/C is cycling between warm and cold air. It will run hot a few seconds after it's turned on and usually gets cold again if I change the air distribution knob to another setting. Like from floor to dash or defrost to dash. Then it will get hot again so I change it and it's cold for a few seconds then hot again... Sometimes it works fine for hours. Could it be the AC Clutch relay or mode door? Searching seems to point to these. I don't know much about cars other than the basics but I'm learning. Replaced my stuck thermostat a few days ago and it has been running great. Had AC for a little and then it started going out again. R134a pressure is good. I had attributed the intermittent cold air to the thermostat sticking and working whenever it felt like it. I hoped it would fix the AC but that wasn't the case. No check engine light. No codes yet. 2008 LS. Thanks!

Welcome to the site, did you change the Dexcool? Did you burp the system?
What thermostat did you use to replace the original?

How's the cabin air filter?

Welcome to the site.

You said " Coolant charge is good" Guessing you mean the refrigerant or freon.
Since you also stated " I don't know much about cars" how did you check the freon charge ? Not a basic task unless you have the proper AC gauges.

Fwiw. Always best to include your cars year and mileage when asking for advice. It helps us to help you since there are some differences between the year models.

Is this new behavior?

It blows hot, even when the temp is turned all the way to Blue?

The AC runs in defrost and recirculate without the light turning on.

Just to be sure you know how it is supposed to work review the Owner Manual. If you don't have one a free digital copy is available from the link in my sig.

It could be the blend door actuator, any noises or clicking up under the dash?

​​​​​​Filters good. Coolant was flushed a while ago. The system was burped. I used whatever autozone gave me. I don't remember the brand could have been duralast.

I haven't noticed it. I'll have to listen again. There is a definite change in air flow when it gets hot which made me think it was the door.

It is important to use a product labelled DexCool, the orange stuff.

Hey, yeah it blows cold then gets hot really quickly. Like the cold was just shut off. As soon as I change the vent selector to something else it usually starts blowing cold again for a few and then kicks over to hot.

Yeah, I meant refrigerant. I have a manifold and gauges and checked it. I can do anything as long as I can see or read about it first. Hi and low side were within spec. I know a little, lol. I research the crap out of everything before I do it. Learn from everyone else's mistakes first. ;)