Ok , now that I have the hitch installed, I can't figure out if my SW is originally equiped with a trailer converter box, or if I need one.
The manual doesn't show any topics on this one. Under the right rear fender
there is a converter type box with one harness going to the rear right lights, and one harness on the other sside that was connected to a large Euro plug/socket. The last being corroded. So I bought a BA converter 7pin to 4 wire kit. This does not fit the connector on the box on my SW.

I am not sure if the set up I have is OEM to all D90's, or if it was installed later. Anyone have any info? or how they connected their trailer lighting on their D90?

Thanks for any info..