Some of the Battery sensors just sits in the hole so as long as it has contact to the bottom of the battery. there should be a sort of wave washer between the sensor and battery tray to keep a light pressure on the bottom of the battery so it can accurately sense the battery temperature.Well, the sensor wasn't even there...just a plug dangling by itselfI bought one and put it in, and check engine light is gone! However, the sensor didn't "clip" into the battery holder at all, it just sits in the hole. Am I missing something that it should fit into?