I seem to remember that the original gauges had purple wire daisy chaining the illumination power from one to another.
That diagram would indicate that it was powered by the key switch and so the gauges were illuminated whenever the key was on. I remember that my old Merc tach was only lit if the motor was running.
Phat is right that it doesn't necessarily need to be on the key. You could power the gauge light from the Nav/Anchor switch.
However, that would mean your gauges are lit even if you are anchored with the motor off or drifting with the motor off. So you would be drawing power for no good reason while your motor is off.
I would say that its up to you as to which gauges you want lit and when.
|