John got the Huco part number correct, I was looking but couldn't find it.
It's best to power it through a relay, and add an inertia switch in as well, just in case.
You don't want fuel everywhere in the event of a collision.
I took relay power from the positive of the alternator, and switch it from the 12v side
of the ballast resistor, as Graham says.
In another thread, Eric recommended wiring the inertia switch on the earth side of the pump,
however, I can't remember the reason for that.