Random beeping sound
 

2015 FR-S

I saw a few posts about this but none had any solution that worked. While I'm driving at random times this loud beeping starts. At first its slow (every couple seconds) then it gets louder and faster, its driving me crazy. I tried changing the battery in the key fob (didn't work) and Its not speed warning from nav (i don't have one). I installed a new head unit earlier this week so i think it may have something to do with that. Someone mentioned possibly adding an additional ground to the unit chassis, but wanted to see if i could get more info.

Head unit: BOSS ACP10

Is there anything (lint, fallen leaves, pokemon) on your passenger seat?
The passenger detection is capacitive resistance and not a weight sensor.
It will start beeping slowly and get more frenetic when it thinks a passenger isn't belted up.

Some times my bag. Isn't there an indicator on the dash when that is happening though? When the beeping happens no new lights or warnings display.

Passenger seat belt light? I avoid putting things on the seat. I had a beeping issue once and it drove me crazy. BLOODY BAG ON THE SEAT!

lol. If there's not supposed to be a light maybe that is it.. I'll test it later.

Somebody is stalking you with an airtag.

The passenger's seat belt light is in the center stack. Easy to overlook. The manual doesn't mention an accompanying beep.

That would make sense because ,my new head unit covers that whole panel. Thanks!