is it electrical or computer or something else?

The other day I changed out my factory radio everything went with out a hitch until after I put the big dash back in. I put it in and started the truck and i heard a pop in the inside fuse panel. The radio checked out all is well tried to shut the truck off truck wouldn't turn off. It started smoking from under both headlight. Smoking stopped i wiggled a few wires the truck finally shut off. I let it be for a day went out checked the fuses all are ok. Got in yo drive it home no transmission indicator, rpm gage doesn't work, no gauges work except oil pressure gauge. The service engine soon light is on. It will not **** properly it starts off in 4th gear and drives in 4th no overdrive. While driving the lights seems to flicker BRIGHTER the back yo normal sometimes when u hit a bump. I have no clue what's up all fuses have been checked and rechecked all them are good. PLZ HELP!!!