Hello, I’m new to this forum but I always look on tech issues and other threads on here. I finally can’t find a post that fits my issues. it’s a 2016 Honda fit. It has issues when the key is off and has been out of the ignition for a long time. It’s not the 15 minute interior light issue. With the key out the interior lights will randomly turn on and stay on, and then turn off. There’s also clicking from the relays in the fuse box, and something near the intake manifold that is powering on after the relays are clicking on and off it’s very repetitive and some time does it 10 times in 30 seconds. The interior lights come on and off and the dash lights come on and off as well as relays clicking. There’s a major electrical issue or something going on. I’ve popped each relay out one at a time out of the fuse box, and it still does the issue .

 

I'd check the switches that sense opened/closed doors, check BCM if these have them (I think they do) for any errors, and possibly the unit itself that houses the relays. Could you get a stethoscope and tell us what relays exactly are turning on and off?