I've got similar headlamp problems which started with the low beam warning. Offside headlamp would start but went off after a couple of minutes. I swapped igniters, and the problem stayed with the offside light. Swapped bulbs, and it stayed. Checked the physical condition of the LCM - water ingress can be a problem for the connectors - all good. Scanned for errors, took a log, then removed bumper and swapped the ballasts. The problem moved to the other side, so I've had a replacement ballast shipped (from a Mercedes dealer, as it was the cheapest route and these Hella ballasts are generic). Will fit in the next day or two and post some pictures.