Outer Limits 4x4 Board

Hi to the group I resently converted my dual fuel 1989 gq 4.2 to fuel injection. In the gonversion I fitted a GU 4.5 efi fuel tank as I needed a efi tank. My question to the forum on the efi fuel pump assembly that you liftout of the tank is also a the fuel level assembly to drive the fuel guage.On the bottom is a float switch which would be the low fuel warning and about 70mm from the top of the assembly is another float switch wired in series with the variable resistor to the guage ( note I do not have a GU service manual explaining this).When this float switch is in the lower position it open circuits the wiring and the guage does not work if you lift it to its upper position is completes the circuit and the guage works. The travel of the switch is only about 6mm .Does any one know what the float switch is for and what it does?

Thanks in abvance and sorry about a long winded question.

Regards
Nigel