Tackled the fuel gauge issues I was having with the sending unit. These are very basic in how they work. I failed to snag a photo of the internals but I'd say if you do not have sending unit that is working pop the cover off and take a look. Make sure you have resistance from the through the mounting post, then through the strap and finally inside the cap where the resistance bar (I'm sure there is a technical term but it escapes me that the moment) is located. If you have resistance to that point confirm the copper tang is still attached to the float arm and is clean. I just cleaned the tang and the bar it rides on and presto I had a working sender. Resistance is 0-90 ohm and will should see 90+ when it is full (by the float arm) and around 40 ohms with a half tank and 0 ohms (roughly) on empty.
Photo 748 - sending unit grounded and powered through factory harness.
Photo 749 - 751 - Gauge showing different positions of the float arm.