Stephen, DO NOT attach a ground to the power terminal, that's called a "direct short", grounds are attached to the case .... checking the sender out of the tank you need to have a ground from the mount flange of the sender to the truck [or dash], and you could/should have a ground from the case of the gauge to the dash to insure the gauge itself is getting a better ground than it may be getting from the mounting

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics