Circuit Description
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The SEO 1 15 A fuse in the engine wiring harness junction block supplies battery positive voltage to both the ground illumination relay switch contacts and the ground illumination relay coil circuit. When the driver or passenger door is opened the body control module (BCM) energizes the ground illumination relay. Current flow is from the ground illumination relay to both outside rear view mirror ground illumination lamps. The ground illumination lamps are grounded through the courtesy lamps relay at G200 and G203.