Daytime Running Lamp Control Unit: Testing and Inspection

- If the park brake switch is CLOSED, the DRL will not turn on the headlamps. The DRL senses if the park brake switch is CLOSED on circuit G9.
- Circuit Z1 provides ground for the headlamps.
- Circuit L20 of the headlamp switch connector has a jumper that feeds the DRL module.
- Check for a blown fuse in circuits A1 or G5.
- The headlamp switch has a 24 Amp circuit breaker that feeds circuit L20.