03 AC always blows heat on passenger side

i had the heater/ac face unit replaced b/c passenger temp control was busted. This did not solve the problem, every once and awhile when i put the AC on, it blows good on the driver side but the passenger side blows heat, and not just a little, its as if the temp was turned all the way up

any ideas?

I used to work for a ford dealer...i know i know, but every now and then we would get a car in doing the same thing on the lincoln ls. They used to temp sensors mounted on either side of the blower box, one for each side, driver and passenger. If one goes bad it has a hard time telling what the dishcharge temp is in the box and the one side blows alot colder or hotter than where you have it set at. Take a look under the dash and see if you see a sensor that might twist in to the case on both sides, if so swith them and see if it now works opposite. other than gettin an actual gm manual i dont know that anythign else would go into that much detail on car liek these that run the dual climate control.

thanks for the advice, i appreciate it

ill do that Asap and let you know

It could also be a bad temperature damper motor or control unit. Not sure if GM uses software, but I work for Volvo and we have actually had software issues cause this.