climate control

While driving I noticed that my passenger air temperature coming out of the vents was significantly warmer than my driver side despite my passenger side being set to 65 while the driver side was 70. I messed around with the climate settings a bit and found while the climate control was Off Dual...

Can anyone tell me why the system would be designed not to allow operation of the windshield defroster and cabin heat streams at the same time? Too, why is it necessary to go to the 'Climate' window to turn off 'defrost'? Wouldn't it make more sense simply to toggle using the button?

Am I crazy or is it impossible to have the climate control mode set to defrost and dash vents at the same time. The buttons on the sync display simply wont allow it. There is no issue setting defrost and floor to run simultaneously. Can anyone confirm? Lariat with dual zone climate. I want my...