This is how I would do it....but I've never done it.....I have torn out an old harness and then wondered why....
I would start by laying out the new harness...compare it to the old one and try to identify where everything belongs when I am done...Then, label the old connections and remove the harness from the truck in sections (like the dash, etc.) I would remove the old harness with out totally destoying it,if possible, and install the new using the diagram and old harness as a pattern.... Masking tape and a sharpie fine point work well to label the old harness....
Does the Chevy duty have the destination printed on each wire?
