My 87 recently failed an army personally owned vehicle inspection because of some issues with exterior lighting. After replacing all the bulbs in the taillights my reverse lights still don't work. What things can i check on that would cause my reverse lights to not turn on. I was also wondering if the center light above the rear window above the bed is a third brake light or just a "cargo light".

 

Have you checked all the fuses? Is yours manual or automatic? Another thing to check is the brake switch is working properly, otherwise you might have a short in your lighting harness.

 

It's just a cargo light.