Tail lights

Note the diagram. Front and rear, you can call them all park lamps, front and rear get voltage from the same source. If the front park lamps work then the problem isn't a fuse or switch. See the A and B in diagram, the A is for front park lamps, the B is for the rear lamps. At the rear, brown wire is voltage and black is ground, use a test light and check both voltage and ground. If the front park lamps work and the rear doesn't, check for wiring circuit problem. Always check voltage and ground, my friend.