The daytime running light is a feature that increases the visibility of your car, so other drivers on the road can see you. And the daytime running light relay supplies battery power to the headlights.
Daytime running light relay operationWhen the DRL relay contacts close, it gives transmits battery power from the LTS fuse to the right and left high beam headlight before it reaches the ground. This process of routing the power through different high beam headlights puts out light at half brightness. It is a necessary part of the vehicle because it allows other drivers to see you on the road.
Common issues with a defective daytime running light relayA defective daytime running light relay can lead to the DRL not functioning properly.