Tail lights not working

Not for tail lights.
GeT a 12 Volt probe screwdriver with the handle that lights up or volt meter. Remove the bulb turn on tail lights clip to any good ground and put the probe tip on the bump at the bottom of the socket and it should lite up. Now clip ground to side wall of socket and probe both bumps in the center one bump is tail the other is brake. Have someone push on brakes and see if they light when on one bump then check tail on other bump. DO NOT TOUCH THE SIDE WITH CENTER PROB OR IT WILL SHORT BE CAREFUL. this will tell you where the problem is,

Also check fuse holder.
leave fuse in clip to ground turn on tail light and probe both ends of fuse for power.

Hope this helps Mike

First check the drivers manual to find the fuse for the tail lights. turn the lights on , probe each of the fuse holder must be battery voltage on both side , voltage on one side only faulty fuse , no voltage, fault between switch and fuse holder, voltage both sides, fault between fuse holder and tail light, broken cable on faulty earth at tail lamp.