Spark

Stop Lamps Malfunction

Battery voltage is supplied at all times to the brake lamp switch. When the brake pedal is pressed, battery voltage is applied through the brake lamp switch and the brake lamp control circuit illuminating the brake lamps.

1. Ignition OFF, disconnect the wiring harness plug at the inoperative brake lamp.
2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect the wiring harness plug at the inoperative brake lamp.
4. Ignition OFF, disconnect the wiring harness plug at the brake lamp switch.
5. Verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify that a test lamp does not illuminate between the control circuit terminal 2 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

7. Connect a 10 A fused jumper wire between the B+ circuit terminal 4 and the control circuit terminal 2. Ignition ON, verify the brake lamps are illuminated.

⇒	If the brake lamps do not illuminate, test the control circuit for a short circuit to ground or an open/high resistance. If the circuit tests normal, test or replace the inoperative brake lamp.

8. If all circuits test normal, replace the brake lamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.