I posted these links in Evldave's $50 Dual Battery Thread in the electrical section but thought they might appeal to folks in this thread too. Here are the links to upfitter manuals from GM, Ford and RAM. They provide documented measurements for all the various layouts of body and bed styles as well as manuals on all the electrical systems. So if you are searching for a hot wire in the rear loom, or want to double check what some wire is that you find somewhere and wonder what system it ties into these might be helpful. Or if you are planning a new build/change of build and want to try to see if something will fit in the wheelwells or whatever, the info may be helpful.
GM:
https://www.gmupfitter.com/pages/body-builder-manuals
Pick your year, then pick the info you want (Chassis info, electrical etc.).
FORD:
https://fordbbas.com/publications
RAM:
https://www.ramtrucks.com/ram-commercial/body-builders-guide.html
GM:
https://www.gmupfitter.com/pages/body-builder-manuals
Pick your year, then pick the info you want (Chassis info, electrical etc.).
FORD:
https://fordbbas.com/publications
RAM:
https://www.ramtrucks.com/ram-commercial/body-builders-guide.html