1992 Toyota Camry electrical

Just bought a used 1992 Camry. It starts runs and drives perfect. AC and heat work fine. The headlights and tail lights horn moon roof power windows power seats and power door locks work fine. The radio cigarette lighter and power mirrors do not work. Can you help me get them going again? The interior dome light overhead works but only when you switch it on manually. It doesn't come on when you open the door. In 2002 the security system was replaced. It will alarm at random occasionally. It doesn't wound when I first open the door. It will sound if I don't start the car soon enough after getting in, There is a wire that has been added at the fuse box located on the drivers side at the bottom of the dash but no one knows what the wire is for. One part is plugged into a probe at the top of the fuse box the other is just hanging there. I am afraid to do anything with it. Any thing you can do to help me?