Hey guys hopefully someone can shed some light on this. I will be running a fuel cell and external fuel pump. I would like to use the factory wiring for the external pump if possible. I checked to factory wiring, the 3 wire plug that goes to factory pump. One is ground, one is constant 12v and the other doesnt register anything until the starter button is pushed. This wire doesnt register anything when the kill switch is flipped to "on" but with kill switch "on" it will register 12v for a few seconds then nothing. Does anyone know if this wire will work for running the external pump? I dont want to use the constant 12v wire because it has 12v whether the kill switch is on or off. Thanks for any tips/suggestions.

I'm thinking relay? If the relay is held magnetically closed to complete the circuit, the ECU breaks that signal or the relay internals do? However, if I see 12v on the out wire, I know inside the relay is hot at 12v to hold and create the magnetism thru the coil winding. Once the relay is hot, it does not care what end of the wires can send in 12v to keep the relay magnetized.

Again too, this is where the signal is T'd to the relay, pump, and ECU. There is a code about to be popped not having that wire hooked up... maybe.

Couple of variables:
1. Left dangling on its own will it start? Yes it will. Then no. ECU/relay cuts off the 12v to the relay as you wait for it to trigger off.
2. Left dangling on its own will it start? Yes, then shuts off. Then no. See #1.
3. With 12v at the wire [that shows 12v then shuts off] is now fed hot from the fuel pump, Will it start and stay running? Yes. Then yes, run a toggle switch between hot fuel pump side to dangling wire side.
4. Bad Boy! Hot fuel pump all the time says is spark still available if fuel pump stops on tip over. Does this switch just cutout the fuel pump only?
5. Have a temp gun at the ready. How hot before the ride is over is to check the relay's heat. That's the piggy box in the rubber boot with the ECU. If it's mile/drag/roadrace and can be shutdown within those type of periods, who knows about touring extending that heat? Only the gun knows for sure.

Thanks Hub. I think you are on to something with that 12v wire. I hooked up the fuel pump to that wire just to see what would happen. It turns the pump on when the kill switch is in the "run" position. Once I start the bike it continues to power the fuel pump. The magnetic theory seems dead on in this case. The pump is working perfectly just like the factory one did without using the full time 12v source. Not really sure the factory one even needed that. I def did not want to use the full time 12v source through a toggle switch (not safe to me). This is a race bike (drag) but I would still like to see how how the relay may get after a run. Thanks!!!

You're welcome. A relay is easy to hook up. That would work, but not as clean as a switch and a low amp fuse to use as insurance. Maybe a 5a or a 7.5a. If the fuse blows that low, then it needs the relay.