Rear body ground problems

[misterss427]

Having issues with both rear lights and fuel gauge ground on 1985 stepside. Anybody have the diagram of how rear harness is grounded to body

 

[fast 99]

There is a ground behind the rear reflectors. Fuel gauge is grounded at the sender. That wire is sometimes attached to frame top rail near the tank. Also grounds at the core support, engine to battery and body. Another ground near emergency brake assembly. I added additional grounds, more never hurts.