Check the wiring on the outside of teh sender assembly. Theres an exposed section of metal between the plastic terminus and the cover plate of the sender asembly that can rot out and prevent power transfer.

Also, check the connection on the sender assembly to make sure you wired it in properly.

If you get continuity at the rear well and the wiring to the sneder is good the pump is likely dead. As for discovering whether the pump is working, just open the cap and listen. The pre-pump is MUCH louder than you think it would be, and if you don't hear it or have to strain to try it isn't working.

-rt