Sorry I don't know the location of the sender off hand, as it would depend on the engine, which you haven't mentioned. Often the sender will be fitted into one of the coolant hoses attached to the radiator. In any case there may be a damaged wire or other connection into the loom further out from the sender. You will need to find the sender, ensure the plug is fully seated into its socket, and trace the wires as far back as you can manage.
I very much doubt any instrument has a fuse except perhaps on the circuit board in the instrument panel.