the electrics on the engine are earthed through the earth on the alt(remember that the engine is insulated through the engine mounts and gearbox mounts otherwise). All the other electrics are earthed via the body through the little earth on the rad support.
I think you will find that the other dash problems are through a bad earth in the dash somewhere.
You mentioned something about changing the reversing light wiring earlier. As soon as you start changing stuff you open a can of worms.
Retrace your steps and you might find the issue.
My other sugestion is forget about voltage readings and go back to basics. Use a test light and just follow the principle that 12 volt electrics are simple. You only need two wires, earth and positive. Find where one of these two are missing using the test light.
Always check the test light is actually earthed too! This can catch you out!
Reply With Quote
Bookmarks