Circuit/System Verification
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, observe the scan tool BCM Stop Lamp Switch Status parameter while pressing and releasing the brake pedal. The reading should change between 1 count and approximately 1023 counts.
- If not the specified value, refer to the Stop Lamp Switch Circuit Test .
- Ignition ON, observe the scan tool TCM Brake Switch parameter while pressing and releasing the brake pedal. The reading should change between Pressed and Released.
- If not the specified value, refer to the Stop Lamp Switch Circuit Test .
- Ignition ON, observe the left, and right stop lamps while pressing and releasing the brake pedal. The stop lamps should turn on and off.
- If the left and or right stop lamps are always on or inoperative, refer to the Stop Lamp Switch Circuit Test .
- Connect a test lamp between the relay side of the CHMSL fuse and ground.
- Verify that the test lamp turns on and off while pressing and releasing the brake pedal.
- If the test lamp does not turn on and off while changing between the commanded states, refer to the CHMSL Relay Control Circuit Test .
- If the center high mount stop lamp is always on or inoperative refer to the CHMSL Relay Control Circuit Test .