2007 Boulevard M50 Fuel Pump issue

Okay, so.

A while ago my dad asked me to replace the fuel pump on his M50 boulevard, and unsurprisingly I realized half way through the job that he had bought a fuel pump for a C50. In a moment of desperation (because the fuel pump for an M50 is $1700) I switched all the wires and mechanisms across to the bracket from the old fuel pump and cleaned it up the best I could. It looked like all the wires and everything were installed back on correctly and so I put it back in the tank and loaded it with high test and put it back on the bike. First off, the fuel gauge wasn't reading but I've read that it can just be a glitch and needs to be run through and refilled sometimes or possibly just that the float is stuck , whatever. The real issue is that upon plugging everything back in and putting the tank back on and attempting to fire it up, the whole display started to spaz out and flash and squeal. I have no frickin idea what it could be, I am able to hear the pump kick on and everything so that's weird. So I took it out and switched the wires back in a different position (they were different on the C50 pump and so I changed them to the position they WERE on the old pump despite it really not looking right) and sure enough, it continued to do the same thing except now I can't hear the fuel pump kick... I'm going to check the fuzes now and see if that's the problem but I was hoping someone could let me know if I did something wrong or if it's just not even possible to make that changeover. The pumps look identical, the only difference is the bracket on which the mechanism is attached.

Thank you, any help or input is appreciated 👍