Part of my fuse box is dead...
 

Was fooling with the AC tonight and I was going to show a buddy the Becker Wonderbar. No wonderbar, no parking lights, no turn signals.

A quick check of the fuse box revealed a bunch of circuits are dead at both sides of the fuses. I figure the "hot" side of the fuses must be towards the cabin. Someone jumped some wires in the box to power the front windows but I was going to sort it out later. I guess now is the time...

No blown fuses, nothing melted etc...

Any ideas on where to start?

Some things, like the headlight fuses, will only get power when that light is on. Other stuff will only have power when the key is in the run position. I'd guess there's something wrong with your ignition switch.

I'd look at a wiring diagram and see if Mercedes used some kind of load reduction relay, or if all the power for those systems (lights, wipers, blower, signals, etc) goes right through the ignition switch.

-J

That sounds like good advice - but just in case this helps => try cleaning the contacts in the fuse box and the fuses they can get a bit corroded.

Thanks guys!

The ignition switch was... well... err...



Unplugged...

I was about to start taking fenders off...

Some circuits are also looped and pass through the fuse box twice. For example the path for the fogs on the W123 goes from battery to headlight switch to fusebox to headlight switch to fusebox to the lights. Maybe with a detour to the stalk switch thrown in for good measure.

Depending on the switch positions both sides might appear dead.