Headlight works intermittently 2001 E320
 

The passenger side low beam headlight on my 2001 E320 works intermittently. When you turn the headlights on it will work but after a while it will go off and you get the "bulb out" fault on the display. After a period being off it will come back on. I have replaced the bulb but that did not fix the problem. Any idea what may be the cause of this problem? I need some direction on how to troubleshoot and fix the issue. Thanks

Start by checking for power at the electrical plug at the headlamp assembly.
Should be power at the yellow wire there.

Assume that your lights aren't Xenons?

Many of the W210's had issues with the wiring INSIDE of the headlight assembly.

Yes, the car has H7 non-xenon headlight bulbs. Since the bulb works intermittently it is getting power, at least when it works. It always comes on when the lights are turned on. But it will go off for a few minutes and then come back on. So it is getting power at least some of the time.

By watching the voltage at the connector when the light goes on/off, you can learn if the problem is in the headlight OR in the headlight switch.

Is your front anti-noise panel in place? If not,water can be a problem in that area. More so with fogs since they are lower. Also, examine the wiring from the headlight assembly to the wiring harness for evidence of any damage. Finally, check the battery area under the rear seat for any moisture. Moisture there can cause electrical gremlins anywhere in the cars circuits. :eek:

I just fixed my 500sl had the same issue. Drivers headlight was going on and off. I change bulb didnt work. I had a little advantage as someone was messing with light socket plug. I squeezed the socket and light would come one. I found socket online for 6 dollars. I got it then spliced it in (3 wires) and now headlamp works perfect. Those lights get real hot and i think it sometimes melts the socket connection to the bulb.

I hope this helps. FYI find the parts online. Dealers are very expensive.

Inspect the plug and wiring, it's not quite enough for the application and overheats and melts. (I just had this happen on my left one.)

MB sells a repair kit for it, list is like $5.50, though my closest dealer quoted $11.70 (typical...).

The connector for the bulb in these units is TWO wire, and that's what the replacement is, too. Apparently the SL driver has a twin-filament bulb in his assembly.

Good luck.

I think it is fixed now. Took the advice above and purchased the headlight "repair kit" from my dealer. It is a bulb socket with a pig tail. Spliced it in place of the original one and so far it seems to have done the trick. Thanks ever one for the feedback.