I did have a chance to go out in the garage this weekend and try your suggestion. The guage stays pegged to empty with key on or off, sending wire on or off and grounding wire on or off, it makes no difference. I noticed that the sending unit is grounded to one of the screws that holds the sending unit in the tank, not a connection to the tab. I believe i have seen in other postings its "OK" that way. Could the sending unit wire to guage be shorted? Should wire go directly to guage or fuse pannel? Seems like next step is pull dash and guage. Thanks for your suggestion!

1965 Chevy C-10 Stepside Pickup