[FRANK PKNY]

You need to start here,
1 you should have power to the tail light switch all the time, if not the problem can be isolated prior to the switch, if yes, go to the tail light on the drivers side and unplug the connectors up under the rear where the junctions are. Mark them so when you go back together you get them correct. Take a long wire jumper and go from the negative pole on the battery to one of the pig tails on the light connect it, Assuming you have a positive ground). You should get one of the two bulbs in that light to fire up. Then do the same on the second pigtail, you should get that one to fire up. If not try making a temporary ground wire go from one of the screws that hold the bezzle on wrap a wire on the screw and go to the frame with an alligator clip to the frame wiggle it around so you get a good connection. If then the light comes on when you have your jumper wire to the battery on one of the pigtails your problem is the ground. Do the same on the other side. by doing it this way you can isolate the problem. I have found that the connectors sometimes get corroded they plug into a female on all the wires there is a male end on the wire and a female connector, I clean them up well or replace the female end (I keep a stock of them) and clean the male end then that gives you a better connection. I put dielectric grease on all the plugs female inside them that keeps from getting water into them and causing corrosion. Hope I made this easy enough. It's just common sense. Report back so we can know if we helped you! Frank PKNY