Hello! I had a removable trailer coupling installed on my XC70 D5 Bj 2006 (6-speed GT) at Volvo. When connecting the fully stocked 13-pole plug of the trailer, the hydraulic pump of the locking differential starts. Sometimes it also starts later. Even after shutting off the engine (default, key removed) the pump runs clearly audible and stops working even after more than 2 hours. My impression is that the pump does not work when the engine is running. Does anyone know this phenomenon or can it be explained? How can it be that the Haldex unit is supplied with electricity in this way? It is controlled by the control units of the ABS or DSTC!? Does it hurt the pump if it runs permanently (apart from the fact that it sucks the battery)? Would you be grateful for your ideas or tips.