The flasher relay is integrated in to the voltage regulator on my ET4 50cc and probably lots of others. The genuine replacement voltage regulator is a few hundred quid new, although I believe you can get 3rd party ones cheaper. Either way not as cheap as £3 and only 24 hours for Amazon to deliver 😄I decided to bypass it and fit a cheap flasher relay instead.

This one linked works perfectly. Thought I'd post this here as I couldn't see anywhere with the info on how to do this. Hopefully will help if someone searches for it in future.

I tapped off the switched live for the horn. You need to remove the terminal pin from the connector to put in the new cable. I didn't have a spare so had to work the old cable loose before re crimping the new cable in. Still needs a little bit of tidy up but works great and is fully reversible if needs be in the future.

URAQT 12V 2-Pin LED Flasher Relay, Adjustable Indicator Relay, Turn Signal Indicator Blinker Relay for Motorcycle Motorbike Scooter
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