You should not need the Furrion Power Adapter # FR69SR for your 2012 Nissan Frontier SV as it does not have the towing computer like newer vehicles. This adapter is typically needed on vehicles 2019 and newer.
Your issue sounds like the power for your camera is turning off. Typically the Furrion cameras are wired to the running light circuit, which will require your head lights to be on for that circuit to have power. If you have automatic head lights it is possible they are turning themselves... view full answer...