Not to give you a hard time but if your going to drive these old trucks certain things are required to keep them on the road. You own a tool box full of tools, right? The tools handle the mechanical end of these trucks. There is also the electrical aspect. You need to be able to troubleshoot electrical issues as they arise, and they will. A VOM (volt/ohm meter) can be had at a number of places for less money than a good wrench. I use an analog meter (Simpson 260) most of the time and love it. The DVM's drive me crazy with numbers jumping all over the place. As with any tool, learn to use it correctly and it will serve you well for many years.

Six volt guy living in a twelve volt world