Fuel gauge reading 8 gal minimum

[turbo kid]

I have a 1985 GN with a dig dash. The fuel gauge reads 8 gal minimum. I now have the sending unit out and it's reading good with my ohm meter.I hooked the sender up when out of the tank and still can't get it to read below 8 gallons. Is there a resistor or something in the dash cluster that goes bad? Help!!