Daytime Running Lamp Control Unit: Description and Operation

CANADIAN VEHICLES
On Canadian vehicles, the low-beam headlamps operate when the ignition switch is in the RUN position and the headlamp switch is OFF.

when the ignition switch is in the RUN position, circuit A1 from fuse 7 in the Power Distribution Center (PDC) connects to circuit A21. Circuit A21 supplies voltage to the DRL module.

Circuit L2O from the headlamp switch connects to the DRL module. Circuit L2O is HOT at all times.

The DRL module receives the vehicle speed sensor input from circuit G7. Circuit G34 from the DRL module provides power for the high beam indicator lamp in the instrument cluster.

Circuit L4 powers the low-beams of the left and right headlamps. When the headlamp switch is OFF, the DRL module powers the low beams on circuit L4. When the headlamps are ON, the multi-function switch powers the low beams on circuit L4.

Circuit L3 feeds the high beams of the headlamps. When the operator flashes the headlamps with the stalk of the multi-function switch, the DRL senses voltage on circuit L3. When it senses voltage on circuit L3, the DRL module stops supplying power to the low beams on circuit L4.

Circuit Z1 provides ground for the DRL module. Circuit Z1 terminates at the left side of the dash panel.