Every other trailer I pull...

[stevesparts]

Had the same problem when i pulled tank that had motors in for the pumps had to add a grounding strap as at some places that we unloaded at the trl. would sit at funny angles and not ground well or some of the trailers where just funky and you be driving at night looking like a disco with the lights flashing away.
but adding a grounding strap should not hurt anything and help with with the not so hot trailers.. incandescent lights...the NOT so good days... "but it was working just a min ago sir" ahhhh memories. :( lol