Last night I remote started my car using the Cadillac ap for iPhone and with the On-star integration - big mistake as it locked out my heater and wouldn't allow me to turn on the heater. Apparently, this might be more common then you think as the dealer was "familiar" with this "phenomenon". To remedy the issue, and gain control of your heater controls again, you need to do a HARD RESET of the CUE. Be advised, this does NOT cause you to lose your presets or any setup; rather it is just like hitting the reset button on your computer when it freezes. Here is how to do a HARD RESET when you loose control of CUE.
1.) Open the CUE face plate (exposing the storage area) - LEAVE IT UP.
2.) Turn the car OFF
3.) Open the DRIVER's door
4.) Wait 30-60 SECONDS
CUE won't tell you that it reset. When you start he car however (and after shutting your door and lowering your face plate) you will see a yellow circle going round and round and that confirms your RESET.
After the reset your heater (or perhaps other) controls will be functioning just fine.
Hope that helps.