have installed my used abn.AHK from Westfalia at the WE , mechanically as far as no problem with it !

When we had clamped the adapter for the connection to the 13 pole.Dose on the lamp control unit, and then turned ON LIGHT , brake light and tail light are connected together with both trailer or vehicle alone.At the same time, the display in BC LAMPE is defective.

Now my question, do I need a new, other switched lamp control ditch? I didn't have one at the AHK.
Furthermore, an AHK was already installed on my V8 and the rear lights have also been groped around with lustre clamps.

I just want to know before I take any more deep E. measures, whether I'm another relay or something. need or if there is a "trick" with it.
Thank you!
MFG Marko F.