GM-GMC: Dual climate control, dual climate, gmc sierra

Question
I have a dual climate control in my 04 GMC Sierra PU. The passenger side will not heat up. It blows cold air when I have the heater on. Wht do Ineed to do?

Answer
The most that you can do is look behind the glove box to see if the heater mode door motor is plugged in and hasn't been jammed by something.  Aside from that, a scanner is generally used to display the commanded position and the actual position.  There are a number of different inputs which the computer looks at to determine whether the heat or cold is needed (this allows for dual controls)  You may need to find a shop that has a scanner to help you diagnose this problem.
Hope this helps.