You didn't give the year of your MBZ. Mine's a '76. If yours is as old
as mine, and you went into your trunk, pulled back the cover and pulled
out the sending unit you'd find yourself looking at a cylindrical
housing that can be screwed off (there are a couple of small holes near
the bottom of the cylinder that allows the fuel to seep into the
housing. This was MBZ's way of dampening the motion of the float in the
sender whenever the fuel in the tank started sloshing around).
Once the housing is off you'd see that the float is like an elevator. It
rides up and down between two wires. The wires are part of the
electrical system of the sending unit. If they or the points of contact
between the float and the wires get fouled, you'll get erratic output to
It's an easy task to clean the wires and contacts to see if that is the
cause of your problem but take care not to stress the wires to the
breaking point in the process.
Lots of luck.
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