hello good morning, the important thing here is that you test the sensor only without the wiring to really verify where the fault is, takex is one of the companies that has a very low failure rate (but it can happen), it measures with a tester the continuity of ALARM terminals, and check if the relay opens and closes correctly without the wiring, and from there you will know where the fault comes from, if from the sensor or the wiring, let me know how it went so you can continue helping regards Andrew