[HotZ28]

This is a typical problem when the battery cable is disconnected without first turning the climate control to the OFF position. Setting to the OFF position will allow all settings to go to the HOME position and should remain there until battery power is restored and the system restarted. Default start-up after a power loss, is the HOME position. If you disconnect the battery with the system ON, the settings remain in that position (whatever they were) so your calibration is off when power is restored. The control head does not have a memory back-up and it depends on battery power to remember previous settings during the next ignition cycle. You can try waiting for the system to recalibrate itself (usually after about 50 ignition cycles); or you can take it to a dealer and have the calibration reset using a Tech II scanner. Good Luck!