OK, I'm used to the term temperature sender. How many wires go the sender? If only one check if there is voltage present, if two check if one of them has voltage. If one wire and has voltage, if you ground it the relay should energize, if two and you connect them the relay should energize.
1971 GTO 455 HO Ram Air
1969 Corvette Coupe with 1970 LT-1 Short Block
2017 Mustang GT