Mystery Knob?
 

I just bought a used 2015 FRS, and it has a knob next to the trunk button and interior light dimmer. It doesn't (seem to) do anything if I sweep it.

Any idea what this might be?

Photo attached.

Thanks!

It aftermarket for sure.
It could be for anything really. The only way to know is to follow the wire behind it.
It could be a subwoofer level control, or a fog/driving lights, or the rear mounted machine guns? Who knows. Only way to find out is to follow the wire(s)

It turns on the flux compacitor..

Subwoofer control?

Adjustable horsepower.

Always wait 3 seconds after turning that all the way to the left before turning it all the way back to the right. Trust me on this one.

Bass knob

Boost controller.

Trolling aside, why not just take that plastic piece of and check what it's connected to?

turbo boost level.

Most likely a sub power knob thing though

Turns the disco ball.

https://media4.giphy.com/media/26FPJ...p0Eo/giphy.gif

Agreed. I think this is the only way to find out.

... Then again, maybe it's for the Flux capacitor.... Just don't hit 88mph. :D

It is a headlight adjustment knob for cars with JDM Headlights only.

Really?, well the US version the switch that controls it is mounted right next to the dimmer switch. Just like on the BRZ.

http://www.cars101.com/subaru/brz/brz13-dash2.jpg