After the Christmas holidays, the company car causes problems with the flashing system. When it is activated, it flashes quickly, as if there was a mistake. All flashers (lamps) flash. Then I saw, someone plugged a 13<>7 adapter into the trailer socket during the holiday season, so use the car and not remove the adapter again. What seemed funny to me, with these vehicles, let these adapters put in the socket, so it comes without trailer to this fast flashing. anyway, the malfunction did not change after the apdater was removed. Monday and Tuesday I was driving around with the hecktic blinking. This morning, I’m going to go, it flashes again as usual, so error-free.Now my question, may it be that the vehicle has a learning counter, when detecting errors ? …in conjunction with the socket of the trailer coupling ? I had read e.g., would the control unit for the trailer coupler fail, short circuit , fuse defective, so it would also come to this fast blinking, and not necessarily only by defective illuminants.