Thanks for the question.
Does the hazards work?
How many miles on the truck?
Try pushing up and down several times on the hazard button, and then see if the brakes and turn signals start working in the rear. Also wiggle the hazard button around. If things start working then the multifunction switch (turn signal) switch needs to be replaced.
Do you have access to a 12v test light?
yes, it is just a test light that lights when you touch one side of it to positive and a clamp is on a ground.
Try this before we go checking for power on wires. Tilt the steering all the way up and try the brakes again and the turn signals. You might have a loose wire going to the turn switch.
Do the turn signals work in the front?
Do the hazards work in the front?
What fuses did you check? Did you check under the hood as well as the interior?
Check the fuses under the hood and let me know if you had to replace any.
So if hazards and turn signals work up front, there is something only in the rear that we need to look at.
Do you pull a trailer with this truck that uses brake lights on the trailer?
Remove one of the rear tail light assembly to get to the brake bulb so we can check for voltage. Let me know which side drivers or passengers side you pull off.
You can pay now if you want and I will leave this post open so you can come back.
Just come back to this post, don't start a new question or post.