1998 Chevy Suburban electrical problem /4X4?

My suburban is having some electlical problems, first it has auto 4x4 I tried to shift to 2 high and transfercase shifted to 4 low it took some time but I got it back to auto, changed switch problem still there, it is a new gm transfercase, next thing that happened, when I tried to start it no luck, checked all conections good jumpered starter and it started, checked every plug I could get my hands on, and it started to work, then stoped again, I have a service 4x4 light that is coming on and off, anti lock and brake light, that keep on flashing, the 4x4 switch lights are off, and now the one that lost me, with the key off I pushed the rear door release and the fuel pump comes on, I checked the grounds to the engine, and frame, even hooked jumper to frame and engine, oh yes and when the key will not start the engine, the wire for the starter coming down steering coulum, is showing 12 volt all the time. It is a 454 with 1000 miles, out of ideas