Roof Rail Reading Lamps
WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
The roof rail reading lamps receive voltage on the inadvertent power courtesy lamp circuit and are turned ON by the individual switch on the lamp assembly.