Dark blue wire is ground for low beam. If there is any voltage to speak of on that dark blue wire, with headlamp switch on, the ground is faulty. Is low beam the problem?
The dark blue wire goes to dimmer switch, from dimmer, a lite blue wire goes to headlamp relay. When the relay is energized, low beam goes to ground.
Wednesday, March 16th, 2011 AT 3:40 PM