Test A: The Red Brake Warning Indicator Is Illuminated and the Yellow ABS Warning Indicator Is Not Illuminated

Pinpoint Test A: The Red Brake Warning Indicator is Illuminated and the Yellow ABS Warning Indicator is Not Illuminated
Refer to Vehicle/Diagrams, Instrument Cluster for schematic and connector information.

Normal Operation
The smart junction box (SJB) will illuminate the brake system warning indicator under 3 conditions. The first condition is when the parking brake is applied, the second condition is when the fluid level in the brake fluid reservoir reaches a predetermined level and the third condition is when there are DTCs in the ABS control module. In the case of the third condition, the yellow ABS warning indicator will also be illuminated.

The parking brake position switch is a normally open switch and is attached to the parking brake lever. When the parking brake is applied, the switch closes and connects circuit CMC25 (WH/VT) to circuit GD133 (BK) completing a ground path for the SJB. The SJB detects the ground and sends the instrument cluster a message over the high speed communication area network (HS-CAN) bus and the instrument cluster illuminates the red brake system warning indicator.

The brake fluid level switch is a normally open switch attached to a flotation device in the master cylinder reservoir. The SJB sends out a voltage along circuit CMC19 (GY/VT) which returns to the SJB along circuit RCM19 (YE/GY). When the brake fluid is at the correct level, the switch remains open and the SJB detects a returning voltage. When the fluid level falls below a predetermined level, the switch closes and connects circuit CMC19 (GY/VT) and circuit RCM19 (YE/GY) to ground circuit GD122 (BK). The SJB will no longer detect the retuning voltage and sends the instrument cluster a message over the HS-CAN bus and the instrument cluster illuminates the red brake system warning indicator.

This pinpoint test is intended to diagnose the following:
^ Wiring, terminals or connectors
^ Parking brake switch
^ Brake fluid level switch
^ Instrument cluster
^ SJB

A1-A4:

A4 (Continued)-A6:

A7: