parking assist monitors stopped working on 2004 Mercury Monterey

My parking assist monitors have stopped working. When ignition is turned on on-off switch shows off. Can turn on and indicator light on switch shows on. When approaching object warning will sound momentarily and then system will shut itself off and indicator light on switch shows off and can not turn system back on until ignition has been turned off and then switch will turn system on but repeats problem when nearing an object. Has anyone got the answer to this problem?

Asked by for the 2004 Mercury Monterey
99% of the problems I have seen are due to a broken sensor in the bumper. When the system spots a sensor issue, it typically shuts the system down.