I had my Furrion adapter on my trailer plug and went to put that end up in the pin box. Thinking I’d keep it free of dust/maybe water etc. Been doing this for years. Well, it was quite a light show in there. Thankfully everything still works. I found one raised connection end relative to the plug that made contact with the inside of the pin box. So, no more plugs in the pin box when batteries on or connected to shore power.