I noticed this once before as well, my only guess was pressurization of the fuel tank as that’s the only thing near there I could trace out, in my case the vehicle was off as well.Can’t find any threads about this. Parked the Jeep around 5:00 then installed a new rear 3rd light. Went out at 11 because i realized I forgot to plug it in in my excitement for new mod installation and there was a humming/buzzing sound from right rear wheel well. Turned the vehicle on/off and it went away. Was clearly off before I power cycled it.
Anyone else notice this?