You are getting the two tip-tank systems confused.
If you have an aircraft that has the "Tips / Mains" switches, there is no pumps that transfer fuel from the tips to the mains. that switch simply actuates a valve out in the wing that changes the fuel feed from either the tips or mains. There is no pumping between tanks. Hence the placards instructing which tanks to use first. If you only require a limited amount of fuel, only put that amount in using the filling procedure specified in the manual.
The fuel selector for port/starboard is exactly that, the switches define which tank is used.
The bright/dim switch is simply there to dim the lights for the selector panel so you don't have two bright green lights in your face when operating at night.
The other system (which you don't have by the sounds of it) uses pumps to transfer fuel from your tips to your mains, which means you let your mains drop to 1/2 tank or a point you are happy with, then transfer fuel across as needed (or use the automatic system which can be a bit touchy)
Joys of BN2 islanders.. no two machines are alike...
Out of interest, whats the rego? Just wondering if I know the machine..(pm me if you like)
Last edited by Me_3; 17th Sep 2014 at 08:56.
Reason: add more info