Here is a short video about the heat shrink wire ends that I use and how I use them. The tools are available at any parts store along with the connectors. I do not recommend doing any wiring on the electrical system of any truck other than right at the light for simple repairs.
Trailer wiring is much more straightforward and simple. Basic repairs are simple and with some forethought, you can do a job that could save you much time and expense. The biggest problem is finding the point that needs repairing, but once the problem is located the repair can be made with confidence.
Till next time, be safe out there.