Fuel gauge readings 72 Blazer 4WD
 

I've gone through many threads & discussion on solving inaccurate gauge readings. I followed the instructions I found and here are results: I disconnected the tan wire from the fuse box and the gauge goes to 1:00, just past full but not to 3:00 like they said it should. Grounding the gauge wire term on fuse box takes it to MT, which from what I read is normal. So with key on and float in lowest position, it reads MT. With it in the up (full) position the gauge goes to 1/4 and stays there.
Any ideas?