Test I: The Brake Warning Indicator Is Never/Always On

PINPOINT TEST I: THE BRAKE WARNING INDICATOR IS NEVER/ALWAYS ON

I1-I4:

I4-I6:

I6-I7:

I8-I13:

I13-I17:

Normal Operation
The brake fluid level switch is hardwired to the ABS module through circuit 128 (VT/YE) and return circuit 512 (TN/LG). When the brake fluid level is low, the ABS module sends a command to the instrument cluster over the CAN circuits to illuminate the brake warning indicator. The parking brake switch is hardwired to the SJB through circuit 162 (LG/RD) and is grounded through the parking brake assembly. When the parking brake is applied, the SJB sends a command to the instrument cluster over the CAN to illuminate the brake warning indicator. The ABS module monitors the brake pressures within the base brake system and provides a message to the instrument cluster over the CAN when a concern exists. If the instrument cluster loses communication with the ABS module, the instrument cluster illuminates the brake warning indicator.

Possible Causes
- circuit 162 (LG/RD) open or short to ground
- circuit 512 (TN/LG) open or short to ground
- parking brake switch
- brake fluid level switch
- ABS module
- instrument cluster