Anyone have any idea where to start on solving the problem of the reverse parking aid not working and in what order to perform these?

 

have someone listen at the back of the car where the sensors are. put car in reverse with hand break on you will hear the sensor clicking . the one that dose not is bad change it you can get one on ebay easy to take out look under bumper press tabs disconnect wire twist and it will pull out hope this helps jrb53

 

Does it not work at all? If so it may be worth checking the module in the boot is plugged in properly and that it hasn't been damaged by moisture. It is located in the boot mounted fuse box, normally tucked down the side. It has it's name written on it so it's easy to spot.