[77newell]

Ken: this is really useful even if you don't have wiring diagrams. When I'm trying to solve any problem the first thing I do is try to get a detailed description of the symptoms. This will help me understand which system has the problem and sometimes it's electrical. If it is electrical then the next thing I do is find a wiring diagram if there is one. If there isn't one then I create one, either mentally for simple circuits or on paper for more complex ones. Then I try to focus on the parts of the circuit that could be behaving in a way that creates the symptoms observed.

There are no circuit diagrams for the older coaches. We have to draw them as we go about dealing with problems. In order to do that we need to either have a pretty good understanding of how these circuits typically operate or find a book or manual that shows typical circuits for a vehicle of a similar age. There is no value in referring to a manual for a vehicle with computers if you have a pre-computer coach. Thankfully our classic coaches do have lists of wiring color codes so if you have a general location for looking on the coach you can probably find the wires you need.