GM Service Manual Online
For 1990-2009 cars only

Brake Warning System Power

The BRAKE indicator has power applied from the 10 a GAUGE fuse located in junction block 2. Power is internally transferred to the multifunction alarm module. The circuit exits the module through connector C2 cavity 9 on a RED/BLU wire. The circuit continues to the instrument cluster assembly through connector C1 cavity 2.

Brake Warning System Ground

Ground is provided to the BRAKE indicator through any of the following components:

Parking Brake Switch

The circuit exits the cluster from connector C2 cavity 6 on a RED/YEL wire and goes into junction block 3. The circuit leaves the junction block at C1 cavity 16 and goes to the daytime running lamps (DRL) control module on a RED/YEL wire to cavity 4 of the DRL module. The circuit continues after it leaves cavity 14 of the module, it moves to the parking brake switch along a RED/BLK wire. Ground is provided internally through the switch.

Brake Fluid Level Switch

The circuit exits the cluster from connector C2 cavity 6 on a RED/YEL wire and goes into junction block 3. The circuit leaves the junction block at C3 cavity 16 and goes to junction block 1 C3 cavity 3 on a RED/YEL wire. The circuit continues after it leaves C5 cavity 5 of the junction block, it moves to the brake fluid level switch along a RED/YEL wire. Ground is provided by C103 through the switch on the WHT/BLK wire.

Bulb Check Relay

When the ignition switch is in the START position voltage is applied to the ST fuse (located in junction block 2) on the red wire. Current continues to SP258 on the BLK/WHT. Voltage is applied to the position switch and if the switch is in the START state (clutch is pressed or the transmission is in the P or N positions) current is allowed to continue to fuse and relay 1. Since the bulb check relay is grounded at G204, the transistor is turned ON. With the transistor turned ON ground is provided for the indicator.