Ok ,, there is a common problem on this unit ,, and the problem lies at the turn signal switch and its connectors and wires ,, the wires and connectors on the back of the turn signal switch tend to come loose and pull out ,, and this causes problems with turn signals and brake lamps ..
so lets do a simple test to see if this is your problem , start the truck up and put the right turn signal ON ,,, then slowly tilt the steering column all the way up and all the way down and see if this starts to make the right turn signal work properly. also give this a try with the brake lamp on the left side ,, step on the brake tilt the steering column all the way up and all the way down and have someone look at the left rear brake lamp to see it if flickers on or comes on
if you get nothing from this action with the steering column , then I need to know if you have a test lamp or a volt meter to do some testing with me
tell me what you find , we can go back and forth on this page