This has probably been covered but I recently bought a caravan with LED lights and got the familiar pulsing of the LED's and issues with reversing sensors caused by the low voltage confusing the BCM or whatever. Anyway I just fitted a portable LED Adapter Module direct from Linear Electronic Design which just plugs in line between trailer and car. It works a treat; it was $245 incl delivery and is very neat. I understand dealers are offering the same unit for somewhat more It's a great solution to the problem of towing trailers etc fitted with LED's. I have included link below.

http://www.linearelectronicdesign.com/

Rob 2009 TD4 SE, Alaska White, Ebony Leather, Sun Roof.

Thanks - currently converting a new caravan I recently bought to LED's, though haven't done tail-lights and running lights yet. Your info will now doubt come in handy when I do.