2000 tahoe non bose premium stereo. I bought this tahoe and it had a crappy old alpine someone had installed. it looks like someone went to great lenghts to modify the original wiring from the amp connector(which is unplugged and has power etc. wires re worked into a monster shrink tube) and there are some issues. i have the L and R front door and R back door but nothing else. no L rear door and no pillar tweets or sub. does anyone have ideas on fixing this? i am used to older model(90s) chevy stereos and this seems a bit more complicated to say the least. where should i start? help would be greatly appreciated as this is slowly driving me insane. thanks in advance! 
