The brake lamp switch can be tested with an ohmmeter.
The ohmmeter is used to check continuity between the pin terminals (Fig. 4).
SWITCH CIRCUIT IDENTIFICATION
Fig. 4 Brake Lamp Switch Terminal Identification
1 - TERMINAL PINS
2 - PLUNGER TEST POSITIONS
SWITCH CONTINUITY TEST
NOTE: Disconnect switch harness before testing switch continuity.
With switch plunger extended, attach test leads to pins 1 and 2. Replace switch if meter indicates no continuity.
With switch plunger retracted, attach test leads to pins 3 and 4. Replace switch if meter indicates no continuity.
With switch plunger retracted, attach test leads to pins 5 and 6. Replace switch if meter indicates no continuity.