[wdfifteen]

I'm trying to fix my trailer lights and can't get the taillights to work.
Flashers work OK on both sides.
Voltage at the taillight connector on the flat 4 at the back of the truck fluctuates all over the place. I plug the connector in and get the same weird voltage fluctuation at the trailer taillight unit. Truck taillights working fine. It's a 2017 Tundra with factory trailer wiring.

On another note, I made the mistake of putting new, cheapie light units on the trailer years ago. They are still bright and shiny inside, but they grab the bulb with such a death grip that getting the bulb out destroys it. Arghhhhh!!