On Pontiac G8's it works like this. Cars with manual climate control, nothing happens at all when remote started. Cars (like mine) with auto climate control will adjust the fan speed, air outlets, a/c compressor on or off and temperature to settings that will result in a inside temperature of 73* F in remote start mode. It also will turn on the rear defoger if needed. One interesting note is that all the settings of the climate control system when the car is turned off, have NOTHING to do the settings while in remote start mode at the next remote start. When you get in and turn the key to on, all the settings revert back to what they were the last time it was shut off. Cool system !