I just purchased an 04 Deville. The a/c works great on the passenger's side. The 2 passenger vents blow much colder than the driver's side vents. Does anyone have an idea of what could cause this? Is this a blend door issue? Thanks.

I have the same exact problem with my 2000 deville.
I have some little pieces of spongy oily foam substance blowing out at times
I think this may have jambed up one of the vent switches.

I am not looking forward to pulling the dash knowing it is designed to break.

Add a can of refrigerant. Common symptom of low refrigerant on a dual zone system. It is not quite low enough to set a DTC.

OK I will add a can. I checked the pressure on the low side and it is 35 psi in 75 deg. F temps. I thought that was the spec. I will add a can just to be safe. I pulled the codes and got B0429. I noticed a thread about actuators but read that B0429 was for the rear blend door actuator. Is this correct or would B0429 cause my hot temps on the drivers side? Thanks Again.

No, B0429 is for the rear only. Been there. It is rather common and may not even be noticeable.

Thanks Ranger. I read your post last night. If B0429 won't effect the drivers a/c I will leave it right now. My car is still under warranty but what happened to you scared me out of taking it into to get fixed. I have a feeling the car wouldn't come back in the same condition I dropped it off.