Pump is inside the gas tank. To pull it, take the seat off. Pull the long rear bolt at the back of the tank. There are two bolts through some grommets at the front of the tank on both sides of the frame, take those out. The top cover has to come off too and I think I had to pull the gas tank filler as well. Been a while since I was in their to replace the warranty-recall breather hose myself.
At the top of the tank, pull off the two vent hoses. They get tight with heat and time. The fuel pump line has a quick disconnect - push that button on the side of it down and the line will pop off.
Now there are two sets of wire connectors into the pump housing: One is for the pump itself and the other for the "Low level" sending unit that triggers the fuel-warning light on the dash. They are tight to remove and I seem to recall they have a little piece you need to pull back to get them off. They have a rubber water-proofing gasket around them that makes them tight too. Don't pull on the wires as they are small and will come out of the metal connector inside the plastic piece.
As to which wires go where, I think the outermost connector of the pump retaining ring is the fuel sender part, so the other is the one you want. BMW uses the color "Brown" as a ground on their newer bikes (at least it is on my GT). So the hot would be the other, although they may use two more wires as I think the pump has 3 (??). Can't recall offhand, but if you want to take the 6 bolts out and pull the pump to look, that gasket will need to be replaced as it used to be some sort of material that swells up when gas hits it to seal. My RT had it in it and it swelled up like a donut once it was taken off and would never go back in. They are about $9 or so. Least the S uses bolts and not that damn huge nut-like thing like the GT has that requires a special tool to unscrew it or a lot of fiddling with a strap wrench. Be careful with the pump piece as it's about a $500 part. My GT ended up with a pinhole leak at the quick-disconnect when I opted to go to the metal one. The pump body housing had some hairline cracks in it and the new metal Q.D. bottomed out and would never seal well. Rode around and the mat under the tank was sopping wet in fuel one day and the smell of gas was everywhere. Should have left that alone. Lesson learned was: "Don't mess with old hardened plastic unless you want to part with $500."
The ignition side would be easier to get to the kill switch of the bar's harness, or maybe the crank's Hall sensor switch. Ignition switch is a cluster of wires with the Key's Fob receiver coupled into it. That switch usually requires a drill to get it off from the underside of it (one-way screws?) . Wire's themselves are a pretty small gauge too. I'd opt for the "Kill Switch" wire but I don't know the color of that one, but you should be able to track it down with a continuity tester at the connector once you disconnect it for the bar. I know the little screw that holds the switch together at the bar is a T-4 Torx (really small and some folding Torx wrenches have it like the one at Harbor Freight for $4.). Good luck.