Start with a hard reset. If that doesn’t do it disable the speaker… Or take it to your local Firestone and let them idjits spend months selling you shit that won’t fix it. I wouldn’t want any part of chasing that down, it’s a problem most would expect fixed for $200 or less and a shop potentially could have $800-1200 worth of time in it to find it….
Something fall into or between the seats. Start fishing around. If there is nothing cycle the seats up and down a couple times while looking for anything jammed up in them. What year is it?
So you should have the rear windows that tilt out? Make sure they are fully closed. Check the tailgate window latch as well. Pretty much everything in the rear of the car will beeb if not latched properly
Ill give it all a good look. Yup on the tilt out windows. When the glass is loose I get a warning up front I think.
So on this model year armada, there is a self diagnostic for the power 3rd row seat. Turn the ignition on three times in 5 seconds. I got the 33 code (three beeps followed by 3 beeps) which means theres no problem with the power rear seat. I did park with my 3rd row power windows open and no beeps. I closed them and got the beeps right afterward. It might be those stupid windows...
You know how zookeepers sometimes hide treats in various places before letting the animals out in their enclosures, to keep them engaged and reduce boredom? We may or may not have paid someone to get to your car at night every couple of days. It's an act of concern and love.
With the power rear vent windows they dont seem to have any open or shut switches. Its just a switch controlling a relay powering two motors. Theres nothing to actually make anyyhing chime back there. Now Im thinking dodgy ground or power wires Its easy enough to unplug the liftgate module Ill see if it does the same beeping when i plug it in.
Is there a child lock on those windows? Perhaps the beep is alerting you that those windows are able to be rolled down by the third-row passengers? Engineers come up with all kinds of safety nonsense like that these days. Perhaps you should alert the local news stations, pull up in front of the dealership, jump out screaming at the building, douse the car with gas, and set it ablaze and then throw yourself on the ground sobbing uncontrollably until the ambulance gets there to take you to the looney bin, that should get you some attention. Just a thought.
It's called the "Annoyatron". About 15 years ago I worked for a company full of cubicles. Yeah, it sucked but made lots of friends there. Bought one of these things and had a field day with it, planting in various cubicles. Guys/gals would tear apart their cubes looking for whatever the hell was beeping. Finally one girl found it under her keyboard (admittedly a poor hiding spot) and smashed it to pieces. That was the end of our beloved Annoyatron. https://www.amazon.com/Funny-Pranks...-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1
I had to wear a beeper back when I was employed. They tested everyone's each Friday at 10:00am to make sure it worked. As anyone who had to wear one for emergency duty can attest, they were a royal PIA. My last day prior to retirement was on a Thursday. We were required to turn in our keys to the department secretary so I placed my keys on her desk but she was on vacation......Prior to doing that I put a new battery in the beeper and locked it in my desk. They either listened to that annoyance for 30 minutes or hammered the shit outta my desk...either way I never did hear how it turned out.
Uh yeah...you clearly got all the bells and whistles. That's where the noise is coming from. Case closed.