Bulkhead wiring harness swap

I'm using a wire harness out of a different year model and the bulkhead is different, but have the same engine and engine components and mine has a relay center and this one has the relay center on firewall close to windshield on passenger side. So, I can't find a harness anywhere and I'm broke from buying a few that don't match. I can't afford to pay someone to make one or do it for me. So, I know I can do it; I have the tools and hardware I just need a diagram of my bulkhead, so I know what wire goes where.