Regarding wiring diagrams, I almost prefer the ones freely available for Morgans given todays electrical complexity on cars. They also show the sub looms and lengths of same. Doubt you would find anything much better for most marques today assuming they were even available. A full one on a modern car would be impossible to trace.
Having said that there are a series (21) of separate diagrams for each aspect of the wiring on my Roadster as well as the schematics broken down into front, rear and engine, all shown in the current Classics parts manual. This makes tracing easier than any other vehicle I've owned in the last 55 years!
If the diagrams were actually readable. The copies I have tried to download on the net are totally not worth the time of the download. If I could actually read it then it might be of use but what seems to be available is a low resoultion PDF file...
