Brake Warning Light

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2001 Mercedes-Benz SL500, 2001 Mercedes-Benz S55, 2001 Mercedes-Benz S500, 2001 Mercedes-Benz S430, and 2001 Mercedes-Benz ML430. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: S430 and S500 models use electronic proportioning to control brake pressure to rear brakes.

Turn ignition on. Dual warning light, mounted on dash, should glow when parking brake is applied one notch and go off when parking brake is fully released.
To check circuit warning sensor, turn ignition on. Release parking brake and ensure light is off. Install bleeder hose and open bleeder screw on one wheel. Slowly depress brake pedal, while catching brake fluid in a container. Light should glow.
Close bleeder screw and release pedal. Bleed hydraulic system (if necessary). Ensure light goes out after testing. If light does not go out, reset differential pressure pin in master cylinder.