Hello all, I hope everyone is doing well this Spring. I am knee deep in the "restoration" of my '93. I hope to post up some pic's soon. Right now I am having an issue maybe someone here can help me out with. I am installing HID headlights in my '93 (in projector housings). I have come across a problem that perhaps others with HID's of knowledge of the headlight circuit in the C4 can help me out with.

The HID setup I have has a HI/LOW solenoid to switch between low beams and high beams. The solenoid has two wires, a ground and a trigger wire. The HID ballast of course has a power and ground wire as well.

This is the way I have the headlight wired up:

At the three wire connector for the factory headlight (in the car harness) there is a tan (low beam), Lt Green (High Beam) and Ground (Black). I have the ground wire hooked to both the HID Ballast ground, and the Ground for the hi/low solenoid (a tiny wire, it requires very little power). To power the HID's I have the tan low beam wire running to the positive side of the HID Ballast. My plan was to run the Lt Green wire to the 2nd wire on the Hi/Low solenoid to switch between hi and low's.

Headlights come on fine and power up no problem there. The issue is when I click the High Beam switch to turn on the high beams, it kills the headlights. I imagine in stock form the Headlight Control Module switches between low beam and high beam (turning off low beams and turning on high beams) when the high beams are turned on.

I believe I need to wire my setup so the low beams are on all the time regardless of weather the high or low's are selected (via the tan wire) and use the high beam wire (Light Green) to control the hi/low solenoid?

I do have a FSM but I am in the middle of assembling the car now as I just painted it. I have not had a chance to really investigate the workings of the Headlight Control Module. I have little time to work on the car and hope someone here may be able to point me in the right direction.

Thanks!

I'm not exactly sure how the HID setup is, but I'll give my take on it.

If the low beam power wire (tan) turns off when you switch to high beam on the dash, then no power will be supplied to the ballast at all when you go to high beams. I think you would need to wire the high beam (lt green) to both the trigger solenoid AND the ballast so that when it turns on there is a trigger for the HID solenoid switch and power for the ballast. So essentially, you would be tying both power wires to the ballast, but only the high beam to the trigger solenoid.

This assumes the HID high/low solenoid defaults to low beam with no power supplied (the lt green/highbeams off).

My only concern is what if by tying both power wires together you could give feedback to the headlight module/switch? I think there is a one way type resistor you can put into the line. Someone better with electrical will have to answer that.

Matthew