G - Noise in subfloor when power is off

[TravisVisual]

Hey All,

Tried searching this a bit before but the answers seemed uncertain. We just got a new to us 2017 G25, I was installing a battery tender, perko switch was set to OFF and in the subfloor there was this sound in the video below. Does anyone have an insight to what it may be? Thanks!

Video of sound
https://www.youtube.com/shorts/7Hurmx3H6OA

[jpwhit]

That's a gremlin. Most boats come with a bunch of them