A/C cold then hot

I have 2004 yukon, while running the a/c the driver side start blowing hot air. the only we can correct it is turn the ign. off and restart the vehicle. Any ideas on what the problem is?

thanks andy-c

I've got a similar problem with my 2004 Denali. It just started today after getting a jump start due to a dead battery. I'm wondering if a sensor needs replacing. Mine works in the rear of the vehicle and when in defrost mode, but blows heat when in regular front vent mode.

Can anyone help?

The only time i've had a similar problem in my 96 suburban and 94 3/4T truck they were low on coolant for the AC. The kits are cheap to check and add coolant, but make sure you get the gauge type kit so you can actually see your pressure. Just follow the instructions on the box and they are worth the $$ when you look at AC work from a shop. Steve