I think the rear avoidance radar is in the rear bumper. The patches on the doors are clearly NOT for stone protection.
They are clear pieces of film over the metal of the door. See pictures earlier in this thread for what is being discussed. I have a 2012 Soul that has these same patches and the 2012 Soul does not have blind spot radar.
The back bumper of the Sorento contains 2 blind spot radar detection units, 2 reverse sensors and the sensors for the auto lift gate function.
See attached parts diagram for rear bumper components.
Also see attached parts diagram where the patch being discussed is called a "stone guard".
Also, here are the instructions for removing the blind spot detection sensors:
Blind spot detection (BSD) unit
1. Disconnect the negative ()
battery terminal.
Be careful when removing the blind spot detection unit. The bracket may break off from the bumper.
2. Remove the rear bumper.
(Refer to Body "Rear Bumper Cover")
3. Disconnect the BSD connector (A) from the BSD unit.
4. Remove the BSD assembly (A) after loosening the mounting nuts.
When removing the BSD unit, be careful not to be damaged the bracket of BSD.