Test Q

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

Test Q1-Q2:

Test Q3-Q7:

Test Q7-Q9:

Test Q10-Q12:

Test Q13-Q15:

Test Q16-Q17:

Normal Operation
The instrument cluster utilizes inputs from the brake fluid level switch, parking brake switch; from the base brake system operation (as dictated by the ABS module) and the communication status between the ABS module and the instrument cluster, to control the BRAKE warning indicator. The brake fluid level switch is hardwired to the SJB through circuit 1305 (DB) and return circuit 512 (TN/LG). When the brake fluid level is low, the SJB sends a command to the instrument cluster over the SCP communication network, circuits 914 (TN/OG) and 915 (PK/LB), to illuminate the BRAKE warning indicator. The parking brake switch is hardwired to the SJB through circuit 1309 (RD/YE) and is grounded through circuit 1205 (BK). When the parking brake is applied, the SJB sends a command to the instrument cluster over the SCP communication network 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 SCP communication network 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 1305 (DB) open or short to ground
- circuit 1309 (RD/YE) open or short to ground
- circuit 512 (TN/LG) open or short to ground
- circuit 1205 (BK) open
- parking brake switch
- brake fluid level switch
- anti-lock brake system/traction control/stability assist (ABS/TC/stability assist) module
- SJB
- instrument cluster