2006 Tundra DC trailer brake lights not working

Are the turn signals and taillights working? I'd check the bulbs first. Then I would take the trailer plug apart and check for corrosion or loose/damaged wires. There may also be a junction box mounted somewhere near the trailer hitch. If everything checks out, use a multi-meter or test light and check for power starting at the plug and working your way back to the lights.

Tail lights are working ok turn signals do not work and the wires look good, . i do have a topper on my truck i wonder if there is wiring to that for the top topper light? it would be in the bumper maybe? Thanks

The problems I have had with trailer light not working are almost always related to the trailer. Trailers are always neglected and miss treated.

Make sure all the bulbs are good

Check that the wires didnt get pinched or chafed apart.

Also check where the light fixture mounts to the trailer if it's not grounded good that could be the issue. Either rust corosion or paint could cause a loss of ground.

My 7pin to flat also has the lights and makes it much easier to find out if the issue is with the truck or the trailer.