Wiring - Help with Locating point B350

Hi All

2018 S3 Sportback. A recent service has flagged a fault with exhaust flap 1 actuator as open circuit. Whilst it does not affect the running of the car it would be good to rectify. I have done some preliminary checks. Flap actuator 2 is fine and the fault does not move when I interchange the actuators. Wiring at the connector is OK. From the wiring diagram, the circuit splits to feed both actuators somewhere in the harness at point B350, “Positive connection 1 (87a) in wiring harness”. Without me having to start dismantling the trim, would anyone have an idea of where this point would be in the car? Thanks in advance.