No water getting in, and I keep it under a carport, dry conditions. The only time water gets on the car is when I wash it and hose it down, maybe that may of done it, however I have now taken the bumper completely out and have the whole wiring with the sensors exposed, I sprayed de watering fluid on all the connections, had a poke about but still not working. I am thinking of buying one or two new sensors from ebay and trying it on each of the sensor sockets, hopefully that will do the trick, I can't see all of them have gone faulty. The fuses are all ok, the reverse light works.
Does anyone know how to test the wiring with a meter? I have a digital meter. I am not an electrician or anything so need some advice.
The bumper took all afternoon to take off. Took a while to work out how, and where all the screws were. Three in the wheel arches, four underneath, take the back lights off and there are two under each lights. You then have to pull out with some slight force, as there are a couple of fastenings above the registration area. I had to drill one of the screws off underneath, rusted and seized causing the star hole to round off!