wiring problems?!
 

So I'm working on re wiring my truck and it is such a rats nest I can't make ends meet, wires are spliced and wire nutted and taped its nasty. So my first question is where can I find a wiring diagram for the cab back so I can concentrate on the tail lights. Also where can I find the stop and tail harness connector and some new tail lamp sockets.
Thanks for the help guys.