Brake Fluid Level Sensor/Switch: Description and Operation

This switch, which is normally OPEN, closes when the brake fluid level is below a certain point. Power (for the switch is provided on circuit G9. This circuit is spliced with the park brake switch, daytime running lamp module (Canada only), and the ABS control module.

Ground for the switch is provided on circuit Z1. This circuit terminates at the left front frame rail.


On vehicles equipped with the optional traction control an additional low fluid level switch is used. This switch is located in the master cylinder reservoir and is used to monitor fluid level. This switch is normally CLOSED. When the fluid level drops below a certain level the switch OPENS. The ABS control module reads this input and turns ON the warning lamps.

Circuits B20 and B21 are used for the switch.