My '78 developed the same issue, the right low beam doesn't work, and neither fog lights are working. ???? Both highs still work.

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1978 240D Auomatic
Custom Charcoal Gray, Navy MB tex, kenwood/Elemental/Boston/Aura sound,
Shaved antenna and emblems.

1990 Lincoln Town Car, Sleeper/Strip car in progress, 17.75@77mph.