fuel sending unit and fuel gauge trouble
Repair Your Fuel Gauge
This should cover it all for you.
That page can help but... There are errors within it.
First; The oil warning lamp does not ground at inst panel. Oil warning lamp and park brake lamp both ground through remote switches. These are the only 2 lamps in any model printed circuit board that require 2 wires.
Second; These gauges and senders operate on a 80->10 range. 80 = no needle movement. Approx' 73 ohms will bring the needle up from its home position to the empty hash mark. You can't break out the calculator and determine half the ohms ( 35 ) is half the gauge range. They don't work that way. As the ni-chrome wire inside the gauge heats up, its per inch ohms resistance changes. It's 13.4 inches of a 1.5 ohms per inch at 68 degrees wire. Heat changing the resistance, generates more heat. And I'm sure that goes over the head of the novice. Anyway...
FACT approx' 23 ohms is half range. That author states 10 -> approx. 100 ohms and then assumes/states 50 ohms is half range. Totally wrong. I should stop there but... There are also gauges containing 13 inches of 1 ohm per inch wire ( varies with application ). So some gauges measure 20 ohms across while others measure only 13 ohms across. The same 23 ohms = half the range applies to all. Now I'll stop.
Just like "open the rallye fuel gauge and bend the little thingy" BS found online. Once its published, it can't be corrected. Or maybe it could be but just isn't. Only the author knows why. Good luck to all
