Installed a Volvo backup warning radar system on my 97 wagon three years ago. It saved me three times (twice in a snowstorm backing up and not seeing a white car behind me). Have had no problems with it until now. The paint began to flake off the sensors several months ago, so I had the whole back bumper repainted, mindful of not putting on too many coats ala Volvo's warning in the installation brochure. Several days ago--three months after removing all the paint from them prior to having the bumper repainted--when I put the car into reverse, the one second warning beep that was normal, suddenly became constant and would go on for five or so seconds or longer, then become intermittent, then constant again. I cleaned the sensors carefully but it did not cure the problem. What's wrong? Has an individual sensor gone bad or the little motherboard, a corroded connection . . . ? Any suggestions on where to start looking much appreciated. If all else fails I will try Volvo customer service, but I don't expect a lot of help from them. Dick