Need help for a/c problem on 05 hummer

[Firefyter]

My wifes H2 hummer has an a/c problem, I think the a/c is the same standard GM a/c in suburbans also, it has dual controls for the driver and passenger. The driver side will blow cold for a while then will immediately blow real hot. meanwhile the passenger side is still cold so I have ruled out a freon problem, I think it may be a diverter valve or sensor, any ideas or solutions?

[tx07]

The controls i think are still vacuum operated. So i think the control has a leak and doesnt let it operate correctly.

[conroebait]

the controls are electric opperated blend doors. they have known problems with them they will basically loose there calibration and not know where they are that is why you are getting the cold to hot blend. take it to the dealer it will be cheeper in the long run then going to a independent shop. they can also proform the diagnostics on it since it is all run through a factory program that the independent garages cant get.

[Firefyter]

thanks