Had a buddy of mine, who owns his own customization shop here in Ohio, put in a set of blue HID headlights and fog lights. The fog lights work fine, on their own switch, but the head lights are giving us fits. They work fine for a day or two, then one decides it doesn't want to turn on. Flip the switch a few times and it comes on. A little later the other head light will do the same thing. We thought it was the switch so I went to Ford and got a new headlight switch. Worked flawlessly for... 5 minutes! Did the same thing. He has put relays in, pulled them out, eliminated plugs anywhere he can, looked everything over, changed ballasts on both sides, changed bulbs on both sides... nothing. Still having a random headlight shut off. Any suggestions guys?

 

Are you running a separate wiring harness for the HIDs or are you trying to use the OEM wiring?

If you aren't using a wiring harness, I'd start there.

- NCSU