Check the fuse box, and replace fuse #5 (your front dome light and brake lights are also on this fuse). Even if it looks good, replace it - there can be a hairline crack that causes the problem. Check all the other fuses while you are at it as well.
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