Dear MBWorld community, I purchased my first Mercedes (03 E500) about 8 months ago. Even though it is an 11 years old vehicle and I have already spent a lot of money in small repairs and maintenance, it has been growing on me.

I learned a lot through different forums. Thanks to everyone for providing a wealth of knowledge. Now, I need your advise, guidance, and/or suggestions about an issue with the factory bi-xenon light. I admit that I have failed to find any forum in which this issue has already been discussed.

Whenever I start the car with cold engine and turn on the lights, both lights come on instantly (as they should). However, once the engine is running for awhile, there is a delay of few seconds to many minutes (up to an hour) for the left light to come on. Similarly, if I go on a long drive during the day, I have to turn on the headlights manually (instead of auto) upon starting the car (during the day). If I don't, as it would start to get dark, only the right headlight would come on (because the engine is hot after driving for however many minutes or hours). If I stop at a rest area or gas station, even though I would turn off the car for 5 minutes, I would leave the lights on (in the manual position). Once again, if I turn off the lights, it may be another hour before the left/driver side comes back on again. Every time the light does not come on (even if there is a few seconds delay because the engine was not warm enough), it gives the error message "Low Beam Left".

Going through process of elimination and attempts to fix the issue, I have replaced the HID bulb, ignitor, ballast, and power control module with different ones (purchased from and later resold on eBay) and even tested all of them by swapping from right side. In addition, I have replaced the headlight assembly as well (for cosmetic reasons). All the connections and wires going into headlights' connectors have been carefully checked. I can't imagine it has anything to do with just the wire, since the left-side delay is there even when the car is not runnin and I manually turn on the lights (with hot engine). Nothing has helped and the left-side HID delay-issue is still there. There is no issue with standard non-HID high-beam, parking lamps, fog lights or side markers - it's only the HID thing.

Are there any specific relays, resistors, fuses, etc that I should look into? Any suggestions to help resolve this issue and make me love this car even more would be highly appreciated!