the fact that it moves to full when the power is turned on shows that the gauge is getting power - disconnect the wire at the sender and see what the gauge does, then short that wire to ground and see if there's a change - also check the wire end to end with an ohmmeter .... if the problem developed during storage then likely either something has gotten corroded or the wire got broken

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