One of my back-up sensors stopped working a few years ago; well, sometimes worked, sometimes didn't, now it never works and all I get is a solid tone when I shift into reverse (the extended solid tone is a reminder that my back-up sensors are inoperable).

When one sensor is out, the system detects a fault and the whole system is "off."

My questions:

1. Is there an easy way to determine which sensor is the broken one?
2. Are these easy to replace? (Mini dealer wanted to charge $280.)
3. Does anyone have any procedures for replacement?

Thanks for any help anyone can give.

Pennstatedan