I have had the 3500 2013 for close to 3 years and the sensor popped off a few years ago (someone hit it) and i got it replaced but the cover to the sensor finally fell off and now the piece keeps on falling out. I tried to just remove the sensor piece so it wont beep but now the switch up front flashes and it doesn't work on the other 3. Any place to buy an extra cover for one sensor?