[BDD]

I already tried moving around the brass spade lug and brushed it and the female connector with a brass wire brush last night. I wonder if the contact cleaner might be able to work its way under the rivet? Hopefully it's not corrosive on the wire. Any thoughts on that? That is VERY fine gauge wire and I do not want to damage it.

I've got a multi-meter. Since it all looks intact its probably corrosion at the rivet.

I do see a lot of oily gunk (the technical term) that settles in the depression on the tank that the sending unit sits in. That can work its way under the rivet and insulate it. This might have been from fuel vapors from the non-existent (before I replaced them) vent lines and whatever else might have leaked through the old, brittle plastic gasket that I just replaced.

I have some very small diameter piano wire, some of it might be stainless steel. If all else fails, maybe a short length of that could be forced under the rivet and form an electrical contact.

I wonder if you could clean the top of the rivet, away from those fine wires, use some flux and melt some solder into it. Maybe that could resestablish a current path from the rivet to the top of the sending unit.