[pauloregon]

Update: I checked the resistance between battery ground and the sender body and found it to be 0 ohms, so this is not an issue of the sender not being grounded.

I replaced the blue/white lead from 6" back from the sender in case the o-ring or last few inches of wire were bad. This did not fix the problem.

Given that the gauge was proven to be good, and the wire is good, it has to be a bad sender. Can't think of anything else. Pelican says "order a new one" so I guess that's my next step. I wonder if FAE senders (vs. VDO) is the issue here.