In what way? Do they come on (turn signals) and have you checked the bulbs? There is a break light switch, break relay, turn signal relay also that could be bad.
They come on in the truck but they do not come on on the back when I turn the turn signals on
Probably go back there with a test light, see if you pick up any power in the sockets. Sockets could be bad. Check plugins for connection, corrosion, Wires in between the front to the back probably good. So, you have a break light switch, & fuse, & relay, Turn signal switch probably ok, check relay, & fuse, plugins & sockets at the rear.
Ok I will do that