Hello all,

I have a 2003 MCS with xenon headlights. During the late fall/early winter, the passenger side low beam started operating intermittently. One day it would work, the next it wouldn't. Sometimes it would not work when I first started the car, but after I had warmed the car up doing errands it would work when I got back in the car. Sometimes it would flash momentarily as I flipped the switch, which led me to try switching the switch multiple times to get the lamp to light.

This worked for a while. Until it didn't. After limping along like this for a while it got to the point that no matter what, it just wouldn't work whether warmed up, switched on 20 times, or cursed at.

It was winter and I don't have a garage, so I put off doing anything about it. I read a little bit about the typical problem here on this forum, namely the igniter. I also found some reports elsewhere that the control module sometimes goes bad. I waited for warmer weather, drove that way for a few months, and tried not to drive at night. I hoped it would start working with warmer weather. It didn't.

Roughly a week ago, I got to work. After disconnecting the battery, I pulled the cover, pulled the socket from the lamp, and pulled the lamp. I found that I had a cracked lamp. Aha, so it was just a bulb after all! Or so I thought.

After I waited for my replacement bulbs to get here, I replaced the bulbs yesterday. The low beam on the passenger side still did not work. So it was a compound problem. I then swapped the control module with the one from the drivers side, but the problem did not move. So it was likely that wonderful igniter problem. Because 2003 is pre-facelift, the igniter is built into the headlight assembly. Wonderful. I pulled the headlight assembly and spent the evening trying to find a reasonable price for a replacement.

I awoke from sleep early this morning and it occurred to me that moisture might be the culprit. I took the whole assembly and cleaned it up. What follows worked for me, but I don't recommend it for you unless you have the proper equipment and/or facilities.

1. I opened the rubber covers from the units to expose the internals of the assembly to atmosphere.
2. I put the cleaned unit in an industrial oven with proper ventilation and heated the oven to 250 deg. Fahrenheit. I chose this temperature to be high enough to vaporize water but low enough not to do damage to any of the headlight assembly components and to minimize outgassing.
3. I baked the headlight assembly for 3 hours, and let it cool.
4. I reinstalled the assembly on the passenger side.

It works!

It will be interesting to see how long it works for. If it fails, I will make sure to post here that it has done so.

 

Good luck!

My 02 xenon went in and out for a while too. Now it almost always works, but is now much brighter than the other side. Im sure it's just a matter of time before it explodes lol.

I also did some reading about the ignitor and module. It seems like just getting a new headlight assembly is the way to go. From what I've read the newer headlights should be a direct fit. Hopefully that info is correct.

The ignitor is expensive and I couldn't find any info pointing to the correct one for our early xenon model. I found some, but it is going to be a guess to get the right one.