On my V70_3, EZ 4_2008, a detachable trailer coupling (AHK) is attached. In the 13-pin electrical box or elsewhere in the wiring there is a defect. Pol 1 for turn signals on the left has no voltage. I worked on the poles with a file and contact spray, no change. The other poles, at least the poles relevant for an old trailer are i.e. the cables in the wire harness to the El.Dose are marked with numbers. Cable 1, which is responsible for the pole 1 for turn signals on the left I don’t see. (In many retrofitted AHK wire harnesses, the cables have different colors by default.) The wire harness on the El.Dose is poured into the plug housing. Is the cast material scraping out without destroying parts? I have tried to find the wire harness on its way forward, in the hollow of the spare wheel and on the fuse box in the D-pillar, at first without success. Does anyone have similar experiences so that I can shorten the troubleshooting with tips? is there more frequent cable breakage or contact interruption in AHK electrics?