I have a few trailers and have been towing with my Vanagons for almost
30 years. My advice is to convert the lights on the trailer to LED but
leave the lights on the van stock. Then use the typical trailer light
converter to bridge the 2 systems, such as this one available many places.

https://www.amazon.com/Hopkins-48915-Tail-Light-Converter/dp/B0002Q81XA/ref=au_as_r?_encoding=UTF8&Make=Volkswagen|74&Model=Vanagon|963&Year=1990|1990&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=1&vehicleType=automotive

Trailers mostly use the same bulb filaments for turn signals as for
brake lights and Vanagons keep these separate and these requires a
special device to translate one to the other for the trailer's use.

Mark

steve meassick wrote:
> I have had a trailer hitch for many years to carry bicycles but an now thinking of towing a trailer.  What wiring kit is recommended to controls the lights in the trailer (4 pin connector)?  I see that GoWesty has one for sale.  It seems that this one is unpowered - can the existing wiring in the Vanagon handle the additional lights?
> Steve
>