I have a year old 2018 Phoenix 921 and when I picked it up I had a hard time getting the tail/brake lights to come on (side lights worked)...used a different truck and they worked. Had a hard time again the other day and then hit a couple bumps in the driveway and they all came on...then my bro-in-laws truck experienced the same issues with the boat after working fine previously ...I thought it was an oxidized ball not grounding/connecting, now I think its in the trailer/female end of the trailer tongue. Anyone ever have this experience? Advice?