On the shifter light, try:
Shift lever backlighting - 1994 E320
On the overheating, do check out the fans as a likely culprit, but out of curiousity, when was the last time the cooling system was flushed and re-filled, and the thermostat checked? 300Es don't like to go without fluid changes every couple of years, as it can impact lots of things, including the water pump. Good luck!
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E