Forward Collision Alert Help Please

[Richard Lippert]

Have a 14 Impala LTZ with the same problem, forward alert system not working. I have ordered rear sensors on line 4 for $23 for  rear facia. Will use phone video camera to determine which sensor is bad. Was to windy today,  will try garage next week. New sensor have to be painted body color.  Don't believe there is any connection with forward alert system. But it seems one after the other  device stopped working. Found information online about how to diagnose which rear sensor using cell phone video camera to listen for beeps from each sensor, place the phone microphone  close to each sensor.  Play back and listen for beeps from each sensor, the  sensor with no beep is the bad one.  Look behind rear facia and pry clips and push from outside to remove.   Hope this will  help someone.   I try to stay away from  Mr. Good Wrench at all cost. 

Richard. L.