1998 1500 fuel pump problem

[Big Foot]

Troll,
Thank you for responding. This is a 1998 1500 and the fuel pump is frame mounted, not in the tank. It has 4 wires going to a 4 pin connector. One red, one blk, one yellow, one red/yellow. I read somewhere that the yellow and yellow/red are the start circuit, and that it switches to the red (positive) and blk (neg) for the run circuit.
I have tried every combination of applying power to all 3 pumps on the bench and can't get any reaction from any of the pumps. It makes no sense to me???
Respectfully,
Big Foot

[Troll]

It's not that complicated. There are two wires, one is B+, the other, ground. When installed on the bike, the ign. switch sends a signal to the ecm on the "unused" terminal (25?) that says that the ign. has not been bypassed. The ecm will then ground the ground wire and the pump will run. If the ecm doesn't see ignition pulses, it turns off the pump after 2 seconds. If it does see ign. pulses, it keeps the pump on. The B+ terminal of the pump receives power from the fuel pump relay, the ecm just provides a path to ground. Here's the circuit diagram. Since it's a J model, I would be suspicious of the ign. switch. If the ecm doesn't see that low voltage signal, it won't turn on the pump.

[Big Foot]

I replaced a bad fuel pump. The replacement won't work. I took the pump off and put power to it on the bench. No matter what I do I cant get either fuel pump to come on, on the bench? I understand that there is a start circuit and a run circuit. I can't get either to work?? Any ideas? it seems unlikely that the old pump and the new pump are bad?
Respectfully,
Big Foot