Tail Light Out, Fuse Good-n-Blinker Works

For starters, Blinker is on top. Tail and brake is on bottom. That may be part of the problem.

Second, your tag lights and dash light are on same fuse circuit, are those on? If out look for different fuse, front markers and rear tail/tag are on different fuses.

Problem still not solved? Bulb in the bottom should have 4 contacts it's bulb number 3157 when you buy a new one. What bulb did you buy? If you put a 3156 (turn signal) in the lower it will only light up when you press the brake pedal.

Also top socket should have 2 metal contacts, lower should have 4.