It plugs into the Radiator Fan relay which I THINK is on the clutch side by the frame, probably in the vicinity of the fuse box. I think the fuse box has a fuse for the fan so it should definitely be close by. Please note the use of "I think" in these sentences. Haha
This Relay box is pretty small and it's certainly something that can get knocked off or pulled off as your tearing apart a crashed bike and maybe forgot to reinstall?