El Conquistador

The headlights have been my biggest issue with this car. I would switch these for LEDs if I could find more information on it.

My left headlight has been out for a few months. I can't figure out what's wrong with it. I just changed the ballast being pretty sure that was the problem. It wasn't, and I swapped it with the one on the right side to confirm the issue didn't follow the ballast. I have 12 volts getting to the ballast, so it can't be a fuse or anything.

I have an almost brand new bulb I bought several years ago when I had problems with the other side, and it didn't fix it so I kept it for testing purposes. It didn't help. To be sure, I intend to swap the new bulb on the right side, but I have to pull the wheel or the bumper and headlight assembly, so that's a weekend job. I wish there was an easy way to check it like with incandescents.

That leaves the cable running from the ballast to the bulb, which was the problem with my right headlight a few years ago. I verified continuity from two of the pins to the bulb receptacle. I'm not sure what the third pin is supposed to connect to, if anything. Of course if this thing is like a spark plug cable, continuity may not be enough.

I'm looking for suggestions on possible faults and things to check before I tear into it again.

speedieone

Check if your control unit has any water in it. This is the same system used on my 2010 Mazda3. On mine water got into the headlight and then into the HID ballast control unit. It would occasionally work then finally not at all. I took the unit out and hit it with a heat gun. Reinstalled and it worked fine.

El Conquistador

I tried my spare headlight bulb in my right headlight (the working side) today and it still worked, so I know without a doubt the bulb is good and the bulb can't be the problem with the left side. Since I've ruled out the ballast and I know I'm getting 12 volts to the ballast, that leaves only the cable that goes from the ballast to the bulb. Again, that was the problem with the other side a few years ago, but the continuity check seemed okay. I guess maybe the insulation broke down or something.

When you say control unit, are you talking about what I call the ballast, the black box screwed onto the bottom of the headlight? I don't know what else you could be referring to. If so, I replaced that with a new one and know that's not the problem. When it stopped working, it was because it had water in it like yours and maybe that messed up the cable. I'm considering taking the headlight out and baking it to see if I can get the cable to work again, but I already dried it out months ago and I would expect any residual water in the cable to have dried out by now if it's going to. I think I'd rather go ahead and spend the $80 or so for a new cable than bother to go through all that effort and with little chance of it making a difference, but I might if someone thinks it'll work. How do these cables go bad anyway?

El Conquistador

I finally fixed it this weekend. It was the igniter / cable. Apparently it goes out pretty easily when moisture gets into the headlight. I sealed it up with so much butyl tape, it shouldn't happen again.