Brake Warning Light System
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1991 GMC Pickup, 1991 GMC Cab & Chassis, 1991 GMC C3500 HD, 1991 Chevrolet Pickup, and 1991 Chevrolet Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Warning system consists of a warning light on instrument cluster/panel, a brake warning light/pressure differential switch (located on brake combination/proportioning valve) and a parking brake engagement telltale switch. Warning light illuminates if brake hydraulic system malfunctions or parking brake is NOT fully released.