I have a 1994 Chevy 2500 non hd. 350 auto 4l60e. Having major issues. Headlights are wonky. Only have driver side high beam. Marker lights work fine. Speedometer doesn't work. Transmission won't shift out of first automatically in drive. It will shift manually. Someone hacked into the wires something fierce before I bought it. I dont know the first thing about wiring.