Have you changed the fuse for the ac blower? Someties they can get a hairline crack in them.
Also depending on the car, the gauge cluster has fuses int he back. they look like the bulb holders but are red I believe.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.