| A SINGLE LAMP DOES NOT ILLUMINATE |
1. Ineffective ground circuit. |
1. Test and repair the open lamp ground circuit if required. |
| 2. Ineffective feed circuit. |
2. Test and repair the open lamp feed circuit if required. |
| 3. Ineffective Light Emitting Diode (LED) unit. |
3. Test and replace the lamp bulb or LED unit if required. |
| A SINGLE LAMP DOES NOT EXTINGUISH |
1. Ineffective feed circuit. |
1. Test and repair the shorted lamp feed circuit if required. |
| ALL LAMPS DO NOT ILLUMINATE |
1. Ineffective ground circuit. |
1. Test and repair the open lamp ground circuit if required. |
| 2. Ineffective feed circuit. |
2. Test and repair the open lamp feed circuit if required. |
| 3. Ineffective BCM inputs or outputs. |
3. Use a diagnostic scan tool and the appropriate diagnostic information for further BCM diagnosis. |