Recently my passenger side headlight stopped working, so I replaced the bulb, but it still didn't work. The bulb works, I tested it. So then I tried switching the actual headlights. I took the driver side headlight & plugged it into the passenger side, it worked. I took the passenger side headlight & plugged it in the driver side, it didn't work. I also bought new fuses and replaced both headlight fuses, still no luck. Any ideas?

 

Unfortunately, this means there is something wrong with the unit's INTERNAL wiring, from the socket to the H7 bulb.
If it was me, I'd just say to heck with the plug and break out the turn signal and high and low beam wiring from the external harness and wire direct thru the rubber caps with some sealant.
The turn signal will require a bit more engineering, anyone have any ideas on that ?
The only reason I mention this is the high replacement cost for headlights.

Here is the wiring :