Need wiring help, big time

[sled_dog]

Something is really wrong with my 1997 C2500 Cheyenne. I need to find a diagram of the wiring harness from the cab back to the taillights. Some reason when I turn on my headlights my rear parking lights do not come on. There is a lot more wrong with them than that but its too much to list. I just replaced beds and only have 1 of 2 ground straps hooked up. First step tomorrow ill be to put another strap on and test it but I doubt thats all the problem is.

 

[sled_dog]

I have a Haynes manual which has wiring Diagrams but they aren't laid out on a chassis like would be helpful.

 

[yunit]

Just had this same problem on my 92. Do the dash lights come on? The headlight switch contacts flattened out, just had to rebend them to make contact.