Alternator/generator/regulator problems of the 1997 Volkswagen Eurovan

My 1997 vw Eurovan camper caught fire on December 8, 2002 as it was being driven on interstate 10 near redlands, CA. It was totally lost. Apparently the fire started under the dash on the passenger side. Vw, after inspection, denies responsibility because an after market radio was installed. The firm which installed the radio has inspected the car and reports that the fire was on the passenger side. There is good evidence of much more heat on the right side. Wire insulation jackets are burned off there and not near the radio. No wires were cut during the radio installation, but rather the radio plug was connected to the vw plug. The vehicle has about 45,000 miles on it. On Nov. 6, 1998, the dealer replaced the regulator motor and the window motor in the passenger door. On June 19, 2000, the dealer replaced the passenger side window motor. On July 17, 2000, the dealer found a loose wire connection when I reported that the speakers were not working since the June 19 repair.