How many brake pads sensors in xf? Where are they? Not oem sensors should fit fine?

 

Brake pad sensors are just a wire loop embedded in the pad material. When the wire is cut through by the disc wearing away pad material the circuit opens up and the dash light goes on. There is no component needed. I am pretty sure there is at least one pad sensor wire on the back brakes. They wear out faster on the XF. I am also curious to know if the front brakes have any.