Bought mine from Chevy Duty and after a little time and a couple of beers figuring out their number scheme, it went like clockwork. The harness usually does come in a few parts. One which runs from the fuse block to the front connections, one which connects through a modular plug under the gas tank area to the rear connections and the main harness from the fuse block to the under dash area. Numbers on the wires coincide with the end connection. Not too bad to do and reasonably priced.
