Tail lights dont work

Oh boy, Chevy uses 3 important wires to make up their tail light harness. Brown is used for your parking lights and yellow and green are your signal and brake light wires, yellow one side, green the other. You have some seriously crossed wires. Start with tracing the lic plate lite since that works. Make sure it leads into your main parking lights and the ground wires from these tail lites aren't cut. The lic place lite will work with just power because the body of the lite is grounded with the bumper. Then make sure that there is power to the signal wires. You can do this with a test light and the signal light switched on. You don't need anyone to step on the brakes since it's the same signal, only interepted. Most importantly, Remove the tail lites and check grounds!! Good luck