1986 Fuel Gauge not Working

[1986K20]

I have a 1986 K20 with dual tanks.  Left tank and sending unit are new.  When I fill either tank the gauge only goes up to about 3/8 full.  When empty it does read empty.  Any suggestions or solutions?

[smokin77]

Mess with the tank selector switch, check all connections, check all GROUNDS!!! I've had ground problems with mine, also selector switch problems.

[RSBAD454]

is it selecting..........there is a way to check if its the guage or the sending unit but i forget what it is.

Toys are my game