No AC. Please help!

[CapitalMark]

My 02 Yukon only blows hot air. I adjust the temp control and no matter what it stays at it's hottest. Last I checked the AC clutch was engaging when the AC button was pressed. Also, not sure if this is relevant, but the battery died during the winter and it needed to be replaced. Heard somehow that could have something to do with resetting the temp control? Any help is much appreciated.

---------- Post added at 12:13 AM ---------- Previous post was at 12:12 AM ----------

Checked AC coolant and it was good.

 

[OR VietVet]

Does sound like the battery replacement may have effected the temp control. I think there is other threads about this but If I recall you just unhook the battery again for about 15 minutes and see if it did recalibrate.

 

[CapitalMark]

Thanks raiderron. I'm going to try that now.

 

[01ssreda4]

Did it work?

 

[OR VietVet]

I guess he didn't have 15 minutes right then?

 

[CapitalMark]

Hey guys, nope, unfortunately I didn't get around to it last night, been waiting for the rain to stop here to try tonight. I really hope it works. Do I have to start the engine with the AC on, or any other trickery to get it to work?

 

[OR VietVet]

Not that I know of.

 

[CapitalMark]

So good news and bad news. I did what was recommended, and sure enough the temperature now adjusts out of hot only. Which is a huge improvement. Unfortunately when I turn it to cold it only comes out barely cool. Guess I have to check freon levels again.

 

[OR VietVet]

Need to know how long the compressor clutch engages for and what the pressure is at the low side, at least. Best if give us the high and low pressures when the clutch is disengaged and when it engages and how long it engages. Sounds like is low on refrigerant. R134A. If do add R134A then just do a can and then give pressures before adding the can and after and how long the clutch engages after the added can. If you put a thermostat in the vents to check how cool remember this: Always check at center vent for a more accurate reading. Initially you can check on high fan speed but the true temp and colder temp will be on low fan speed. Less fan turbulence means a colder temp reading. That is why the best way to do it when first start out driving with a/c on is to get the heat out with the high fan speed and then adjust fan speed down to get the colder temp.

 

[CapitalMark]

Thank you so much, Ron! Probably have to wait until Thursday to get to it, but I'll update when it's done. I really appreciate your help.