I noticed the driver's side headlight was not working on my 98 ML320.
I tried instaling new bulb, stiill no luck.
I swaped bulbs between left and right side, driver side light sill out.
I examined fuses, both are good and even tried switching fuses.
Turn signal, parking, and high beam lights function on both sides.

Any ideas what could be the problem ?

Does anyone know if the combination switch has a separate circuit for each headlight or one switch to control both ?

Thanks

Check your fuses. I THINK the left and right headlamps are on separate fuses. I know from experience the left and right tailight are on separate fuses.

Good luck.

Yes, there are two fuses (#34 and #35 if I recall), and both looked good. I even interchanged them and just to make sure. Thanks

Obviously I need to read more carefully. Sorry I couldn't offer any new help.