I have a 2021 fatboy I finally got the fuel tuner does anyone know where I plug it in?

 

It plugs into the diagnostic port. It is a grey connector located under the seat. It should look something like this.

 

FWIW.....

I don't own, nor have I ridden, a new mono-shock softail.... but based on a pic on the Vance & Hines website.....

I believe the 2021 Fat Boy, and the FuelPak 4 that connects to it, are for Harley's new Delphi MT22 ECM. That ECM has a slightly different data port... and it is red now, instead of the older grey ones...

Additionally, I believe the new mono-shock softails, have a cover on the left side of the bike, under the seat, where the data port is located...

Here is the pic I referenced from the V&H website, of an FP4 plugged into the data port of what I believe is a 2021 softail...

 

You do realize warranty is void once you install that? None of my business where youre taking it, just checking youre aware.