UPDATE: Battery WAS bad. Hooked up new battery and tail lights, Tail lights work but I haven't run them long enough to see if fuse blows. Horn went off when new battery was installed so it is now disconnected. I may use an add-on button; there is no horn relay. Truck fired up nicely but alternator is not charging (checked with volt meter). I will take the alternator back for bench testing. Could the horn problem be causing the tail light problem as there is no fuse for the horn?
