If the fuses are all good, then give the potentiometer a work out.
The potentiometer (dimmer) should be somewhere in the instrument cluster (not sure about location on your car), the trip reset is a knob that protrudes from the gauges and the potentiometer looks just like it, usually on the opposite side of the cluster. On some models the trip reset and potentiometer are a combined unit. Once you figure out which is the dimmer, twist it stop to stop (l-r) several times, this will help to erode the corrosion on the contacts that has most likely built up over the years.
I had the same problem on the 280 some time back, and after a little work out, I too could see paradise by the dashboard lights.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.