When reverse gear is engaged the positive signal (INT/A) for switching on the reversing lights moves via the junction unit uunder the dashboard B02 and supplies the parking sensors control unit M84 at pin 1 connector A via pin 8 connector D. See E2022 REVERSING LIGHTSThe control unit M084 is earthed at pin 16 of connector A.The parking sensor speaker P44 receives signals from pins 2 and 10 of connector A of the parking control unit M84; pins 9 and 6 of the same connector are bridged.The control unit M84 provides a power supply and reference earth to the four parking sensors K97 from pins 6 and 1 of connector B respectively.The four front parking sensors K97 sends signals to connector B of the control unit M84:- to pin 5 the left external rear sensor K97E;- to pin 3 the left internal rear sensor K97F;- to pin 2 the right internal rear sensor K97G;- to pin 4 the right external rear sensor K97H;