I totally agree. You know they have to have a drawing of some type in order to built the units & include the needed wiring for all the fixtures, exterior / running lights, pumps, refrig, etc. This is not brain surgery! Just building an RV. I am sure now that I have gone through the whole RV electrical systems from front to back, they do have certain color coded wire for specific types of systems. If they would just supply that is would have been a lot easier. I used a trouble shooting light and went from wire to wire with the unit hooked up to my truck to figure out what I needed. I now have a wire int he back cabinet with 12 volts and ground for a future radio, auxiliary from the truck to the rear of the RV and all lights for a vehicle or secondary trailer behind including a wire fro trailer brakes. At the same time I installer a power converter and an onboard generator, so now I have a through understanding of the entire wiring from front to back. I any one needs in pointers just give a shout. I will probably be able to help as much as Heartland, at least I am willing to provide what is in my RV anyway.