The brake fluid level switch on the brake master cylinder reservoir provides a hard wired ground input to the instru-
ment cluster circuitry through the red brake warning indicator driver circuit whenever the fluid level in the reservoir
becomes low. On models equipped with the optional ABS system, the CAB continually monitors the ABS system
circuits and sensors to decide whether the system is in good operating condition. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument cluster. If the CAB sends a lamp-on message after the bulb test, it
indicates that the CAB has detected a system malfunction and/or that the ABS system has become inoperative. The
CAB will store a Diagnostic Trouble Code (DTC) for any malfunction it detects.
For further diagnosis of the brake indicator or the instrument cluster circuitry that controls the LED, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). The park brake switch input to the instru-
ment cluster may be diagnosed using conventional diagnostic tools and methods. Refer to the appropriate wiring
information. For proper diagnosis of the brake fluid level switch, the ABS, the CAB, the PCI data bus, or the elec-
tronic message inputs to the instrument cluster that control the brake indicator, a diagnostic scan tool is required.
Refer to the appropriate diagnostic information.
8J - 110
INSTRUMENT CLUSTER
KJ