ECM question on 05 traxter 650

bought this old turd with the intent to get it running, looks like someone was taking parts off it but not anything that can’t be replaced.
making progress but I noticed the ECU has one big plug and two small gray wires going into it. ONe of the gray wires goes to the ground terminal of the battery, but the other one is broken and I can’t find the other end to determine where it’s supposed to go.
Anybody have any ideas? I’m guessing +12V but i don’t want to fry it if that’s not correct.