I don't know if any of them are for the running lights etc but as others mentioned, on ours, if you pull out the power centre metal box from under the fridge onto the floor a ways, you can see behind it.
There are a couple of clumps (joined with giant wire nuts) of white wires of various gauges that seem to be "just there" that are the grounds for all sorts of things.
(I had trouble one time with the ground for the Winegard and it was one of those.) PITA . You stand a good chance of losing the ground on something else while fixing the first thing when putting the clumps back together with the giant wire nuts, so you have to confirm everything works after that, not just what you fixed. :)