Fuel Gauge Only Reads 3 O Clock

[Graham57a]

I have been chasing down a fuel gauge issue for months now so I'm calling in the experts. My truck is a 72 c10, all factory wiring harness. Here's where I started:

1. I freshened up all of my factory parts when I did the restoration, everything worked before I tore into it. After I put it all back together my gauge would only read at 3 o clock.

2. I replaced the sending unit with a brand new one, I swapped everything out and it still read 3 o clock.

3. I robbed a very clean factory fuel gauge out of a wall art cluster I had and put it in the truck, cleaned up all of my connections, checked the brown wire from the sender to the fuses box, still hasn't moved the needle....

I tried disconnecting the wire from the sending unit and grounding it to a fuel tank bolt to see if it would move, no luck. Then I tried freshening up the resistor on the back of the gauge and cleaned the contacts on it, nothing. I took out my sending unit and made sure the ribbon cable is not grounding itself on the tank and still can't locate the problem

Does anyone have any idea what to try next? My next move is to buy another fuel gauge by it seems like it would read below empty (9 o clock) if the gauge was bad. Any ideas would be a huge help

Thanks guys