On my '79TD, I've had a problem arise, and wonder if any one else has had same. When I switch on the high beams, the driver side light goes out. Both low beams work fine. I replaced the sealed beam with identical bulb, to no avail. Does this sound like the headlight switch, or something else?

I was once told by a very experienced electrical tech, that when oddball stuff happens, it is a ground problem.
Check the quality of the ground connections. The other thing to check is that mickey mouse buss the h/l assembly plugs into. Just wiggle it and see if the lights will come on, of go out. Seems that I had to work the connections in there to get one of my lights to come on.

I had sort of a similar problem in the past on my F-100, and it was caused by the switch. Yesterday I helped fix another similar problem on a friends car, and it was the bulbs, so we just replaced both bulbs and that fixed the problem.

When I get time, anyway. Does sound like a ground. In the mean time, it goes on "the list". At least I've got both low beams, I can't stand having just one head light. I guess with a Benz, its kind of up scale red neck.

We used to say, when you drive in to Alabama, you have to stop at the boarder and kick out one head light!