2000 BLazer 4 door 4x4. The fuel guage always reads full or will wiggle between full an 3/4. Heard this could be a ground issue but I can't find the gound for the life of me. I know its supposed to be attached to that frame somewhere below the drivers tail light but I can't find it anywhere. Could this be the ground? The pump works fine.

 

could also be the sending unit for the gauge on the pump. Known to have issues. Only way to fix is tull the pump