Find the hatch, its about a metre behind the drivers seat, Unscrew and take off.(mines under my new floor, glad i left access



Unlpug the wire loom, take a new wire (earth) fit a ring on one end,
and fix under one of the screws holding the fuel sender, give it a bit of a wire brush clean first.

Then push the other end (bare wire) into the plug (the one with the black wire) then re-attach the plug onto the sender unit.(i also put a bit of wax-oil over the ring terminal to keep it from rusting)


When done, just put everything back.
You can do the earth fix from underneath the bongo, This may be the only way if you have no access from above.