Low fuel light on all the time

[mikeyfev1]

My low fuel light is always on in my 85 300D when the key is in the ON position. It was working correctly after I removed the sender and performed an internal cleaning. Worked correctly for about 1 year; then started this "on all the time" behavior. I have re-opened the sender and found a lot of gunk in the bottom of the tube; I carefully removed all of that, cleaned things up and reassembled everything. I still have an always on condition. Gauge functions fine.

Is this something that can be caused by an bad ground somewhere? If so, does anyone know where that ground point would be? TIA.