same old story parking sensor help 75 tourer

[Mac-1990]

hi all,

thanks for taking the time to even bother looking at this age old problem. im on my second 75 now running a diesel 52 plate tourer. she has parking sensors which you guessed it don't work. now I know the switch on the gearbox is a go to fix normally, but when I put the car into reverse more times than not the car gives off the sound to say the sensors are engaged. but after that they don't do anything at all?

any ideas?

thanks again