I have both of those harnesses. The engine harness that connects to the 42 pin connector and the engine compartment wiring harness that does the remainder of the wiring for the front end of the truck. PM me for the particulars.
I need this same harness but one from a manual without all the automatic control systems. Or if someone could explain how to splice an automatic one to work for a manual that would be great!
The only difference in the wiring between the two is the small harness that plugs in under the truck and goes to the transmission. You can swap auto to manual, change the transmission harness, swap for a manual PCM and go to town, everything else is interchangeable.
Or you can make a wiring change and use the auto PCM if you like. There is a connection that needs to be made to make the PCM think the truck is in neutral (so it will start) but aside from that the wiring is the same.