vshortt,
I think I have all the same stuff as you (heated seats and mirrors w/ DATC) and I played with it on the way home. I think if you want to change the temp for the entire cab, you hit the Dual button (until the Ext temp shows on the pass side), and then hit the Auto button on the left side by your RED/BLUE buttons. i think that that makes it work the way that you want. Then if you want the pass side at a different temp still in Auto, just hit the dual button again. If you ever want the manual control, hit the OFF under the Auto and you have 2 sides again. Hope that helps.
