Brake Light Switch: Testing and Inspection

NOTE: Before proceeding with this diagnostic test, verify the adjustment of the brake lamp switch to rule out misadjustment.

If the electrical circuit has been tested and the brake lamp switch is suspected of being faulty, it can be tested using the following method.
1. Remove the switch from the vehicle.





Fig. 24

2. With the switch in the released position (plunger extended), use an ohmmeter to test each of the three internal switches as shown. You should achieve the results as listed in the figure.
3. Gently push the plunger on the brake lamp switch in until it stops.





Fig. 25

4. With the switch in the depressed position (plunger pushed in), use an ohmmeter to test each of the three internal switches as shown. You should achieve the results as listed in the figure.
If you do not achieve the results as listed in both figures, the switch is faulty and must be replaced.
5. Install the switch in the vehicle.