Fuel Level Sending Unit

[hadam]

In my 1997 E-420 W210, I am having problem with fuel gauge.

Most of the time it show my tank is full. I know the problem with sending unit.

I got following part number from MB Stealer for Fuel Level Sending Unit 210 542 41 017. The part cost is $109.

Is any one know how to change the fuel level sending unit?? Any help in DIY process will be greatly appreciated.

[Peter Guenther]

Before pulling the sending unit check the resistance of the sending unit, I think if the connector is off it reads max. Fill the tank, check the rsistance drive a hundred miles or so and do it again. With a variable resistance box you could simulate it to check the guage. Otherwise plug in the new one to see (they might not take it back since it is electrical)

[hadam]

Do you know what resistance in Ohms I need to simulate the fuel level sending unit.

Should I start with 3.3K ohms and work down ward ?

Let me know.

[Peter Guenther]

All I can find is that the resistance increases as the tank gets empty, that must mean 0 at full and probably a few hunderd ohms at empty. Start high, in my 140 manual you can not change it with a full tank, and it has a ring holding it in the tank that is loosened by a plate with two pins. there is a "o" ring below the sender. It shows removing the tiner the sender is in the top rearward side.
From my "boat" experience it is usually 0-300 ohnms for a sender but you never know with the Germans

[Peter Guenther]

I just found another document that says the opposite, low resistance on empty, high on full!