02 SLS electrical problems

There could be several different concerns, not necessarily related. A seat heater malfunction is a common concern, the year of the vehicle saw problems with elements and there is also a service bulletin to back this. The garage door opener has circumstances that often fall on the opener you are trying to synchronize them to. Map lights could be bulbs/switches, or power supply. The windows could be logic lock, and corrected with disconnecting the battery and shorting the cables together.