My wife told me that her passenger side daytime running light was not working. So I picked one up on my way home from work and installed it. Turned on the car and no dice. So I check over all my hook ups and all is good. All the other lights work including the low beam light when it is switched to high beam except the DTRL. I took the light assembly out on both sides and plugged in the passenger side light assembly into the driver side harness and the DTRL in the assembly works. So which wire in the harness controls the DTRL to the headlight assembly? and where does it go to? somewhere along that line there must be a break or bad connection. But I need to know which wire it is that I need to back probe.