Fuel gauge and speedometer/odometer not working 1993 bmw 318is

fuel gauge shows empty all the time, flickers when the key is turned but never shows any fuel even with a full tank, i checked out the fuel level sending units in the tank, both are ok, and the issue with the odometer/speedometer is that it never works at all not even a flicker.. are these common problems with the bmw's and is what is causing these issues?? any related info would be helpful.. thanks in advance