aux wire

[Tavo1au]

Hi All, I don't have any power coming from the black wire at the trailer plug , I tested it with the engine running could someone give me some advice please..

[numberplate]

Black wire , pin 2 , is the reverse signal. do the car's reverse lights work ? its not always connected , and if it was connected you may have a blown fuse at the ECU which controls the trailer socket. or the ECU is faulty.