62 Valiant dash lights

if gas gauge is pegged low...sounds like an open circuit ie a broken wire to the tank sender, disconnected at the sender or the sender resistor is open or tank itself is not properly grounded to the car. Easy to test this with a VOM. If your temp gauge is working, it is powered by the same CVR thus states supply and control voltage is operating. So with this in mind, scenario two could be open between CVR and gauge, verify that the input to the gauge from the CVR is a pulsed voltage being applied.