DLR (day light running lights) and trailer lights problem

I have posted this in the A4 B9 section as well as here.

I have an issue with my trailer. All is working electrically except the DLR function is not putting the lights on the trailer. If I go to normal lights (not auto and day lights) the lights come on the trailer. The indicators, brakes, dipped rear lights, rear fogs all work. I also checked the electrical connections on the trailer and all are well.

I am not sure but wonder whether as the car are LED ( Audi A4 B9 model) and the trailer old style bulbs could it be that the current to the trailer connection is insufficient?

Anybody had this issue?

Thanks in advance.