When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Did you ground the lug or the threads? Threads should be grounded, and the lug should go to the relay. Lug and threads should not have continuity (~1000 ohms) at low temperature and should have continuity (~25 ohms) when hot.
You have to see if that's like-conductive to the lug or if it's the other side of the thermostat. You should be able to see the silicone isolator. Big threads need to be grounded, little threads (or 1/4" spade connector) go to relay.