I have a 1996 Mark VIII with 56,000 miles. Uo until yesterday, everything was running great. Today, it doesn't start, the fuel guage pointer is about an inch to the left of the full mark. The radio doesn't work, the center information pod that shows time, fuel mileage, etc. doesn't work and the headlamps and tail lights turned on by themselves. If this is a ground problem, where exactly would I look?