I just found out from a friend that the 3rd brake light on my 2021 Edge ST blinks a few times continuously while I'm stopped and have the foot on the brake. After doing some research and taking it to the dealer (still under warranty) they told me that the previous owner have installed some aftermarket wiring to make it blink like that. I would've been fine if the light only blinks on hard braking while vehicle's moving, but having it blink while stopped is just overkill and must seem obnoxious to the drivers behind me. However, the dealer said they could remove the wiring and restore the factory state for $200. Obviously, I declined and would like to see if I can find the wiring mod myself so I can disable it.
If anyone could share some idea of the aftermarket mod that may be causing this particular type of brake light behavior and where I should look to find and disable it, I'd greatly appreciate it.