I lost the high and low beams awhile back. Passing lights worked, so I narrowed it down to the combination switch on the column. The switch is easily removed and I found a broken solder joint on the switch. Re-soldered the switch and it worked great after that.

Good luck.

__________________
Paul

1991 300TE (280,000)
1985 300TD (432,000 miles - retired)
1976 300D (225,000 - retired)
1975 300D (165,000 - retired)