B250 -89 electical problem.

This is a strange one... The horn, the cig.lighter, the door locks and the rear fan do not work unless the engine is running and the headlight switch is turned on. The engine must be running, only putting the ignition switch in drive position does not help.

When the engine is running and headlight is on, a silent buzz comes from the buzzer (which should sound loudly if you forget the headlights).

All fuses I could see have been tested = OK. Also, I could not see any loose ends among the cables.

Do anyone have any good solution? If not, I'm in bad need for a circuit drawing and wonder if you know about some homepage which has such downloadable?

You have a bad fuse or fuse link. look under the hood for the fuse link.

Could also be the body electrical cables (ground and/or positive) these are connected straight to the battery (the thinner cables)