[prkaye]

The float-type fuel sender works by creating a resistance between two terminals, dependent on the position of the float. Instructions say to test the unit with an ohmeter by touching the two terminals on the assembly.
However, once the unit is installed in the tank, there appears to me to be only ONE point of electrical contact... that screw on the base plate. Where does the other wire go? Do you just ground it? I want to be sure I'm not missing something before I seal the tank up today.
Phil

 

[lrfrey]

Ground, Phil. You can then move the float and watch the meter value change. If the tank is sealed, roll the tank and watch it.
Larry

 

[Paul Eastham]

Ground, Phil. You can then move the float and watch the meter value change. If the tank is sealed, roll the tank and watch it.
Larry

In other words, the flange of the sender (the part with the screw holes in it) -- which will be grounded to the airframe via the screws...
Put one probe on the center screw and the other on the flange.

(I was a bit surprised by this design too)