2005 Trailblazer. When tank is full, guage reads empty. When gas level drops to between 1/2 and 3/4 it starts reading normally and works fine all the way down. I thought if the guage sender went bad, like a break in the resistor, that it would read normal when full then as the tank level lowered to the break it would suddenly drop to zero. Does this guage work opposite of that, or is it likely that the resistor is corroded and needs some type of cleaner?