LED lights on trailers are very hit and miss on a car-by-car basis in my epxerience. We build trailers at work and my PHEV often tows them. I have a witter towbar fitted (aftermarket) and it usually works OK, we have had a few problems with LED fog lights that have required the fitting of load resistors in the light to make it work still.
I am not actually a fan of LED lights anymore because you can never guarantee what sort of electrics a customer's vehicle will have and dumping big, expensive load resistors into lighting circuits just adds cost, heat and complexity.
My last car was a Mondeo (61 plate) and that had all sorts of problems with lighting. We used an L200 to tow (2010) and that had very basic electrics and worked perfectly. Customer's transit would light everythign but couldn't drive LED indicators.
