Does anyone know where the main wire that provides +12v to the 100% brightness pin on the DRL LED come from? What i mean is that each headlamp unit has the 100% +12v pin and the 50% +12v. The wire that comes to the 100% pin, i need to tap into it. One way is to remove the bumper and tap in on each end but ideally i want to try and find out where this wire is coming from as a single wire before it goes to each headlight and that way ideally I can tap in before it splits to go to two headlamps and also save myself having to remove the headlamp itself.

Do the lexus tech docs wiring schematics show this kind of information?

 

I'm guessing the DRL system is controlled by a module (I don't know where it is) that uses pulse width modulation to get full or half brightness. Or maybe the lamps are in series/parallel but that's an older way of doing it not sure your car has that.

What are you trying to do?

 

There are 3 wires providing power to the LED's It is the wire breaking off the normal harness and enters into the headlight toward the center of the light though the round cap.

White = Ground pin #17
Green= +12V DC pin#16
Black= +12V DC pin#18

The dimming of the lights is actually controlled on the LED board itself.