Chosen Solution
1985 Mercedes 300 cd turbo head and fog lights do not turn on have replaced all fuses, checked ground on passenger headlight corner passing light lever on turn signal will make headlights work therefor its not the bulbs rear defrost out cruise control out tachometer works, speedometer works, turn signals work , rear lights work, hazard lights work. no loose wires apparent help please
Have you read and completed this guide to w123 fuses and fuse box service ? How to check Mercedes W123 Fuses