Originally Posted by Jim Bennett
It definitely should not use grounding through the hitch. There is a dedicated wire ground wire in the trailer plug.
I agree. Although the hitch and ball do form a connection between the tug structure and trailer frame, this is not a reliable or appropriate ground connection.
Andersen offers a line of nylon-capped aluminum balls
, which (in addition to not requiring grease) clearly do not provide an electrical path... which doesn't matter, because - as Jim said - there is a wire for that.