Mine went out too - found the sensor was inop. caused by rubber particles plugging the passage to the internal switch, which of course required a new rear brake hose - which was found at a dealer.net search halfway across the country (with none shown available in the regular H-D parts depot ). The hose was failing internally where it attaches to the rear brake caliper, I'm assuming because at prior rear wheel removals no one tied the caliper up but let it hang on the hose. If your switch has particles in it inspect the hose and see if particles come out when you bleed fluid thru it. If so the caliper needs cleaned out as well, my back brake was intermittently failing from the same particles plugging the passage into the caliper. Good Luck with it, hope your hose is OK !