here's the factory wiring for use with dual tail lights - you're maybe missing the "crossover" wires at bottom center, which weren't used with the separate turn lights, which is seen bottom of this page

Bill



Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics