Chevy & GMC Vans

I'm having many issues with lights in the cab.
Reading lights not working unless doors are open.
Overhead center light not working.
Tv not working. No power to any of it in accessory mode or engine run mode.
Any wiring schematics out there for this custom work? Relay bank location? Where is power tied into?

welcome to the forum.
First step is I would check all the fuses. From the factory, some are in the fuse box under the driver's seat, and the rest are in the fuse box under the hood - driver's side. Relays are there too.
Factory schematics are on charm.li and gmupfitter.com

What is 'Sherrod' ? Is that done by a conversion company? If so then modifications won't be covered in factory service info. You'd have to get schematics from them.