Fuel sending units read WRONG time after time!

Thanx 64ragtop.

A couple posts ago I wrote
"Nothing that would cause the lights and gauge to error like this. It must be the way the cluster is grounded, as that is the only thing common to all the errors.
I just had a thought. I have the light switch unhooked from the cluster. I am on my way to look into this"

That is the path I am following now. As I sit here I am thinking that on the bench it was hooked to the wall ground thru the power supplies I was using, not the car's ground.
I need to follow up on this.