Electrical Circuit
WARNING: This page does not describe the selected car, but rather 46 other vehicles, including the 2001 Pontiac Montana, 2001 Pontiac Aztek, 2001 Oldsmobile Silhouette, 2001 Oldsmobile Bravada, and 2001 GMC Sonoma. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect wire from switch terminal on combination valve. Connect wire to ground. Turn ignition on. If brake warning light does not come on, repair brake warning light bulb or wiring circuit. If light operates, brake warning light electrical circuit is okay.
NOTE:
On Astro and Safari, system is not equipped with pressure differential switch.