GM Service Manual Online
For 1990-2009 cars only

The CTSY fuse and the LPS fuse supply voltage at all times to the following lamps:

    • The courtesy lamps
    • The dome lamps
    • The reading lamps
    • The IP compartment box lamp

The following lamps turn on when the headlamp and panel dimmer switch or one of the door jamb switches close and provide a ground path:

    • The courtesy lamps
    • The dome lamps
    • The reading lamps

The switches on the IP compartment box lamp and the vanity lamps provide ground paths when the switches close.

For more information, refer to Body Control System Circuit Description in Body Control Systems.