I just replaced my rear fuel tank on my 94 f150. Sending unit not working now. Haven’t used tank in about a year I’d say. Sending unit worked perfectly fine before though. Could the sending unit have gone bad, or maybe it just needs time to be able to start reading correctly again?

Welcome to the site..
Not working, reading what level if any?

Could be an issue after the swap with the sender itself, or, the brass type floats likedl to crack under the ‘C’ portion of the senders arm. If cracked, the float fills with full and sinks to the bottom of the tank always indicating empty..
There’s no relearn...

Reading on cluster is past full. All the way past full to where arm won’t go over anymore on it

If the sender wire shorts to ground, you’ll get an extreme high reading.,

Okay, I’ll have to check it out then. Thank you!