Exterior Lighting Systems Description and Operation: Export
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
When the driver presses the brake pedal, the switch contacts close and the stop lamp output signal is supplied to both left and right stop lamp assemblies and to the center high mounted stop lamp (CHMSL). The stop lamps are grounded at G401.