Messed up Fuel Guage

I have a 1989 Ford Bronco II.
The fuel gage will sometimes go to the full position or simply wander
around.

I understand that this is the result of a short somewhere!
I understand that the Sending Unit can "Open" showing a empty fuel
condition.

But can the sending unit create a short, showing a full fuel condition?
This is so intermittent its driving me nuts.

Up in the instrument cluster some where there is what they call a "Splash
Module" Actually its a gage control that keeps the gage stable while the
fuel moves around in the tank. Can this Splash Module be the problem?

I've attempted to disconnect C114 cable and measure the yellow\white
wire to get a resistance. The problem is I think that I'm also
disconnecting the ground in that I can't get a proper resistance reading.
I don't want to have to build a break out box.

So I'm just wondering if any of you folks out there have a Bronco II with
a wondering gas gauge!

Thanks!