From what I see that looks like alarm system crap. I have removed way to much of it over the years twist wires are usually a give away.
It's honestly not that hard and you will have a very intimate relationship with your truck when finished.
Hey Pinatball you can probably find a Hayes or Chilton manual for your truck for $20, They have perfectly usable wiring diagrams in them. I tore out a whole garbage bag of aftermarket wiring out of my truck. Also, if you are having problems with headlights check out the dimmer switch on the floorboard. They wear out all the time. Cheers, Chilli...