| HEADLAMP DOES NOT ILLUMINATE |
1. Ineffective or missing bulb. |
1. Test and replace headlight bulb if required. |
| 2. Ineffective ground circuit. |
2. Test and repair open headlight ground circuit if required. |
| 3. Ineffective feed circuit. |
3. Test and repair open headlight low beam or high beam feed circuit if required. |
| 4. Ineffective left (lighting) multi-function switch. |
4. Test and replace left (lighting) multi-function switch (clockspring) if required. |
| 5. Ineffective BCM inputs or outputs. |
5. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |
| HEADLAMP DOES NOT EXTINGUISH |
1. Ineffective feed circuit. |
1. Test and repair shorted headlight low beam or high beam feed circuit if required. |
| 2. Ineffective left (lighting) multi-function switch. |
2. Test and replace left (lighting) multi-function switch (clockspring) 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. |
| HEADLAMPS WILL NOT SWITCH FROM HIGH TO LOW BEAMS, OR FROM LOW TO HIGH BEAMS |
1. Ineffective left (lighting) multi-function switch. |
1. Test and replace left (lighting) multi-function switch (clockspring) if required. |
| 2. Ineffective BCM inputs or outputs. |
2. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |
| 3. Ineffective shutter mechanism. |
3. Test and replace shutter mechanism (headlight unit) if required. |