Brake Switches

Brakes switches are electrical devises used in automotive brake systems to warn either the driver of a possible malfunction in the brake system, or to warn the other drivers on the road that your vehicle is slowing down. All brake switches function in the same manner by using a plunger that moves back and forth in the switch, closing or opening the circuit to the brake lights or brake indicator light.

There are three types of switches used in an automobile's brake system. These switches include pressure-differential switches, brake fluid level switches and brake light switches.

Pressure-differential switches are used on dual master cylinders to warn the driver of loss of brake pressure by triggering the red brake light on the dash. Both the front and rear portion of the master cylinder direct brake fluid to this switch, which compares the pressure, and the brake light is illuminated in the event a "difference in pressure" is detected.

The brake fluid level switch is used to alert the driver when the brake fluid drops below a certain level by activating the red brake light indicator on the dash. These switches are float-type switches that are located in the master cylinder reservoir.

Brake light switches are used to alert other drivers behind you that you are slowing down by illuminating your brake lights. These switches are located in the brake pedal bracket underneath the dash and the plunger portion of the switch rests against the brake pedal lever. When the pedal is depressed, the plunger completes the circuit activating the brake lights.

Click here to view our brake inspection page so you can determine if a switch has failed. The following steps will show the removal and installation of each switch mentioned above.

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