Brake Warning Indicator: Description and Operation
CIRCUIT OPERATIONWhen the Ignition Switch is turned to "RUN," "BULB TEST" or "START," voltage is applied to the Instrument Cluster through CKT 39 from Gages Fuse 9. The Brake Indicator receives a ground through CKT 33 by any one of four components: the Ignition Switch, Park Brake Switch, Brake Combo Valve (ABS) or the Electronic Brake Control Module (EBCM).
When the Ignition Switch is turned to "BULB TEST" or "START," CKT 33 is grounded through the Ignition Switch. When the Park Brake is set, the Park Brake Switch closes, grounding CKT 33 through the Park Brake Switch.