turn signals and parking lights stopped working
 

A while back, > 6 mos., the left indicator light on the dash
stopped illuminating but the actual turn signal would work properly.
I figured it was a dash bulb out and ignored it.
Today I started the car to find the dash, parking and turns were all dark.
Fuse 12 is good.
The light switch functions in running and headlight modes but not parking.
The multi function stalk operates the beams and wipers but no turns.
Any ideas?
Where do I begin tracing this?
Andrew

As far as turn signals you may want to check the 4 way hazard switch. If this switch is bad the turn signals will not work. As far as the other dash lights I would suspect a bad ground for the instrument cluster (a common problem for W123 cars). Remove the instrument cluster and attach a new ground wire from the back of the cluster to the ground point on the steering column support. Mercedes uses brown colored wires for ground. Make the wire long enough to ease future removal on the instrument cluster.

*2, you can buy a ground strap at Autozoo or Napa. Just run it from one of the screws on the cluster to where Mr. Whitmore mentioned.

Ground issues gone!

Thanks, I will check and report back.

turn signals back still no parking lights
 

Before I made room in the shop and drove the car in, I gave the warning flasher button a push.
The flashers work fine and now, so do the turn signals.
Still no parking lights. Would the ground from the cluster to the column address this?