GM Service Manual Online
For 1990-2009 cars only

The fuel door latch actuator shares the circuit with the driver door latch assembly. The body control module (BCM), upon receipt of a lock switch lock or unlock signal, will switch the appropriate door lock actuator, as well as a fuel filler door release actuator control circuits to battery positive voltage. The opposing side of the door lock and fuel filler door release actuators is connected to ground by the I/P fuse block through the other door lock actuator control circuit and the doors, along with the fuel filler door release, will lock or unlock as commanded.