Yes, there is a much easier way. You don't nee to remove the bumber. Simply remove the number plate then pop off the trim that runs along the middle of the bumber. The trim from each side meets in the middle behind the number plate. Gently prize off the trim and this will give you access to remove the sensors. Try swapping the faulty sensor with a good one to see if it starts clicking. If it does it will be a faulty sensor. If not, then it's the wiring. Be careful when you remove the sensors not to damage the wiring by trying to prise them off. There are some tricky clips on the edge that require a fine screwdriver to release the catch. If you don't loosen the catch you risk pulling the wires from the plug and making matters worse. Familiarise your self with how they come on and off by getting under the back of the galaxy and looking at the rear sensors and how they unclip. Good luck.