Brake Light Switch: Testing and Inspection

Brake Lamp Switch Test






• Before proceeding with this diagnostic test, verify the adjustment lever on the back of the switch is in the adjusted position. If the lever is in the non-adjusted (diagonal) position it may have never been adjusted.

If the electrical circuit has been tested and the brake lamp switch is suspected of being faulty, utilize the scan tool and monitor the inputs from the switch to the PCM. The switch can also be tested using the following method.

- Remove the switch from the vehicle..

- With the switch in the released position (plunger extended), use an ohmmeter to test each of the three internal switches as shown.

- Gently push the plunger on the brake lamp switch in until it stops.






- With the switch in this depressed position (plunger pushed in), use an ohmmeter to test each of the three internal switches as shown.

If you do not achieve the results as listed in both figures, the switch is faulty and must be replaced..


The switch can only be adjusted once during initial installation of the switch. If the switch is not adjusted properly or has been removed for any reason, a new switch must be installed and adjusted.

If the switch is found to be operating properly, it may be misadjusted. .