Except Silhouette, Trans Sport & Venture
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 1999 Pontiac Montana, 1999 Oldsmobile Silhouette, 1999 Oldsmobile Bravada, 1999 GMC Yukon, and 1999 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.
Pressure differential warning switch in combination valve energizes brake warning light on instrument panel when front or rear brakes lose hydraulic pressure. After repairing failed side of hydraulic system, depress brake pedal with moderate to heavy pressure to hydraulically center the piston. This will turn off brake warning light. On vehicles with Hydro-Boost, insufficient flow of power steering fluid to the hydraulic booster system will turn on brake warning light.