Weird Electrical Happenings-Part 1, ...turning headlight knob effects full gauge Options

[7TPorsh]

I have a bunch of little weird electrical things going on...so i'll attack one at a time:

The fuel gauge (stock combo gauge) moves as follows under different conditions:

- Ignition off/headlights on- turning headlight knob up makes fuel gauge go from empty to full; turning down go back to empty.

- Ignition on/headlights on- fuel gauge show reading...turning knob up increases the reading on the fuel gauge by 1/4 tank; turning down decreases...so 1/4 fluctuation in the fuel gauge depending on how the headlight knob is turned.

Tend to think the full bright on the headlights translates to a closer fuel reading. But why? is the power source for the fuel gauge incorrect?

I checked the schematic, but it looks like a Lucas engineer designed the wiring for the combo gauge.

[7TPorsh]

Well i checked around...behind the front trunk pull above the fuse box was a bundle of brown wires (about 11) are twisted together. They weren't even grounded. Sheeesh!

So I put clips on them and grounded them to the frame behind the speaker cover.

Now the tach, oil pressure light and gen light work. Yahoo.

But... the gen light goes on now with the parking lights...not the headlights. Did I miss a ground or did i ground something I shouldn't have. The voltmeter goes down a volt or two when this happens.

Also Part Two problem isn't fixed with this.