GM Service Manual Online
For 1990-2009 cars only

The garage door opener, located in the overhead console, is a three button switch that receives power through CKT 40 (ORN) from the courtesy lamp feed. Battery voltage is hot at all times to the switch. Ground is supplied by G400 through CKT 150 (BLK). When the headlamp and panel dimmer switch is in the HEAD or PARK position, power is received through CKT 9 (BRN) to light the LED's when the headlights are on.