general problems of the 2002 Chevrolet 1500

I pulled into driveway and put car in park, left engine running. Went to door of residence to get my kids. Kids went out to the car and were yelling fire! I seen the inside up in smoke. I reached inside to turn engine off. We then started pouring buckets of water into seat and on floor around the seat to try to prevent spread of the fire. I luckily put the fire out. Fire dept unhooked battery and removed melted plastic around seat. It seems a wire somehow shorted out beneath seat and caught the seat and floor on fire.

When I started the engine the gas gage went to full then back to 0. Later when I went to use the tow/haul it would not work, it wasn't long before the odometer and shift indicator stopped working.