Instrument lights on 92 500SEL
 

I've read most posts regarding Instrument lighting but my problems seems to be unique.

I currently have only one instrument bulb working behind the cluster which only partially lights up the speedometer. I obviously checked all the bulbs first and also "wiggled" them in their sockets - to no avail.

However, this is where my problem is strange. When the light switch is in the 'Parking' position, I have no instrument lighting at all and only left-side parking lights operate. When I turn switch further to the 'Headlights ON' position, then all exterior bulbs function correctly...but only speedometer lights up on interior (and all aux. console lights too). I checked all the fuses and they are fine, however, fuse #9 (for right side parking lights and license plate lights) has no power on either side when headlight switch is in 'Parking' position.

I'm suspecting something foul with the switch itself. Or am I looking in the wrong area?

Please help!

Constantine