Random Beeping From Inside Dash No Lights On

I have a 2017 TRD Sport. About a year ago I swapped the head unit for a Boss touchscreen and replaced the speakers. The previous owner did the lift kit, added hood mounted ditch lights and raptor lights. About 2 months ago I started getting a random beep sound unlike any other sound the truck makes. It sounds like it's coming from within the dash and I can't locate what it's from, where it is, or what's causing it. Took it by my Toyota dealership today and just played a video recording of when it happens and the tech said he'd never heard it. I pulled the head unit off and unplugged my dash cam. Still beeps. It's high pitched, beeps about 7 times, 5 seconds apart. Any ideas??? It happens at random times while the truck is either driving or in on mode (just before starting engine). It only happens once a drive. So it could happen once in a 20 minute drive (at any given time into the drive) or once during a 90 minute drive, but no more. No indicators on the dash display.

 

Airpod tracker battery is running low?

 

YouToyota

 

Probably a stretch here, but I wonder if the truck has the dealer installed alarm/tracker unit still. Maybe something in the unit is causing it to beep when it shouldn't be? Back when I worked on Chrysler dealership vehicles, they would often mount the control unit behind the knee panel under the steering column. Worth a shot I suppose, can't think of anything else off the top of my head. Hope this helps!

 

There watching you....