Wifes Escape had a burned out headlight on the drivers side. There has been some moisture in there so it was no surprise it was out. Bought new bulb, discovered a LOT of moisture was in there so I drilled a small hole to drain. I had removed the assembly last year and removed the moisture, so there is a definite leak in there.

Anyway, new bulb didn't work in the car. I tested both bulbs with a 12v battery and they both work fine. Must be a wiring issue.

I checked all fuses, and swapped all the relays around to no avail. Any ideas?

Today I'm going to pull the assembly out again and see what I can find. I just find it odd that the other headlight works fine.

 

They started some years ago adding monitoring circuits for exterior lighting and got fancier in the later years that they even set codes.

 

There were no codes on this one, so I took the headlight unit out and found the problem.

The connector at the back of the headlight that has three pins in it (ground, hi, low) it was full of rust and grime, and one of the pins broke off. That was the low beam pin.

Ran a new wire for the low beam from the bulb connector, out a small hole drilled in the housing that I sealed, and bypassed the exterior connector altogether for that wire. Cleaned up the connector and put in dielectric grease.

Also figured out why there was so much water in there. The bulb was not seating properly as you could not twist it all the way. Just have to twist really hard for some reason.

Seems fine now and should not leak. I will plug the drain hole I drilled in a couple of days, I want it to completely dry out for now.

 

The improved monitoring with codes was added years after yours.