Thanks, Gary. I get all that part, as it can be deduced from the wire diagram. What mystifies me is that putting a ground on the Y/G wire activates the flasher, and removing it stops it? If that's so, why does the flasher still work when the cancelling unit is completely disconnected? I'm beginning to think there is more to this particular Nippon Denso FN257C unit than the standard 3-prong flasher. So, will any other 3-prong flasher, able to handle the wattage, work?
No need to answer any of this. I'm just thinking out loud.