It would help to know what bike
The original two-pin has one wire for supply and one wire for the switch. The three-pin electronic uses these and also calls for an earth (at least the one on mine does).
On the 750 (and I think 550) Honda supplied a spare earth wire (green under the left side panel) with the same female flag connector as those on the two-pin flasher, so I've always assumed the purpose of that earth wire was to give you the option of fitting a three-pin unit. Or maybe the loom is standardised and different spec bikes have the three-pin already? I don't know.
Anyway, the three-pin I used has these markings -
Terminal 49 to Supply Terminal 49a to indicator switch. Terminal 31 to Earth.
Easy to fit, once you work out which of your two wires are which (black is supply and grey is switch IIRC), with the spare earth going to 31.
The one you have does not appear to call for earth, this is what I found on the interweb -
Terminal P to Vehicle Warning Lamp. Terminal X to supply. Terminal L to Indicator Switch.
I have no idea how you would, or could get that to work as you don't have a convenient wire available for the P terminal. My understanding of electrics is pretty basic though, so hopefully others will set you straight.
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