I've been having issues with my passengers headlight. I already replace the ballast and the igniter but sometimes it won't turn on and I have to fiddle with the connection between the headlight harness and the vehicle harness. I noticed that if I turn my headlights on before I start my car the passenger side headlight turns off when the starter is engaged. Has anyone else had this issue?

 

Sounds like a fault in the harness. Moisture in the molex connector, wire breakdown, etc. What is the condition of the fenderwell splash shields? Damage to harness or moisture in the headlights is 80% likely due to water or road debris being kicked up. Best guess at this point.

 

You can always try swapping components one by one (bulb, igniter, ballast) to the other side and see if the problem follows the part. You can at least narrow it down and rule other things out by doing that.

 

I did that when I found out the igniter was bad. After replacing it I swapped them and they both worked. Everything is brand new in both headlights.

 

I am guessing, but it could be your Headlight Control Module. I had to replace the HCM in my car when the passenger side fender liner came loose and road debris and moisture hit the exposed electronics and parts.

 

I believe he already replaced the ballasts in the car. Or did I misread something?