| BRAKE LAMP DOES NOT ILLUMINATE |
1. Ineffective or missing bulb. |
1. Test and replace brake lamp bulb if required. |
| 2. Ineffective ground circuit. |
2. Test and repair open brake lamp ground circuit if required. |
| 3. Ineffective fuse. |
3. Test and replace the fuse if required. |
| 4. Ineffective feed circuit. |
4. Test and repair open brake lamp switch output circuit or stop lamp output circuit if required. |
| 5. Ineffective switch. |
5. Test and replace brake lamp switch if required. |
| 6. Ineffective BCM inputs or outputs. |
6. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |
| BRAKE LAMP DOES NOT EXTINGUISH |
1. Ineffective feed circuit. |
1. Test and repair shorted brake lamp switch output circuit or stop lamp output circuit if required. |
| 2. Ineffective brake lamp switch. |
2. Test and replace brake lamp switch if required. |
| 3. Ineffective BCM inputs or outputs. |
3. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |