Tail light wiring - OE harness to LED lights | Toyota First find the tail light wires in your wiring harness, and mark them. Then find your brake light wires, and mark them. Then find your left, and right turn signal wires, and mark them. Ok, tail light wires go to your LED lights, brake light, and left, and right signal wires get hooked up to the converter according to the instructions for it. wwwngconcepts wwwngconcepts NewHilux • View topic - Tail lights wire colours what Just it time for me that you ask this really as i got it all working and went to plug in the trailer on the weekend and brake lights ended up flashing with the indicators. But when its not plugged the tail lights work fine. So not sure what ive done wrong. i think i need the wiring diagram aswell.