So after this last ice storm here in the Midwest my Fit thawed out and now when I'm driving the door ajar light comes on and off rapidly and I can hear the rear hatch opening and closing itself over and over. After driving a bit (and repeatedly stopping to close the stupid thing) the light stays on except when the brakes are applied. Also, occasionally it will start without the brake applied when the ignition button is pushed. Since I've already had soooo much fun replacing most of the electrical system, just like every Honda I've ever owned, I figured I'd reach out and check around if anyone else has this problem before I tear into the door. It seems to me a lot like the issues the CRV a few years prior had when they recalled the hatch actuator due to faulty seals on the door and shorting out. I haven't hooked up my HDS tool yet to run diagnostics yet. I almost just don't want to fix it since I'm thinking about trading in for a newer 6 speed. Any input is welcomed.
2015 EX 192k miles

 

Best guess would be a broken solenoid/actuator on the hatch. That would explain why it keeps trying to close and lock itself - it can't close with a broken actuator, but it keeps trying.

 

I haven't experienced this problem but if the hatch just won't stay closed then it could be as simple as WD40 on the mechanism followed by some silicone lube or something more specialized for the task. It's been pretty cold here and a lot of the greased components on my Fit are pretty sticky. If it's the solenoid firing away then my best guess would be a loose connection and you get the pleasure of ripping apart the door.

 

*FIXED*

Decided to get into it since it wouldn't stay locked and I didn't want anything to happen to my expensive sound system. It only took about 5 minutes to pop out the actuator and check the solenoid. Sure as grandma's got gout, it had gone bad. I'm a bit surprised still how much this car is like Legos and most stuff just snaps together lol I guess there's pros and cons to that as I've learned. Anywho, problem solved. Thanks for the replies. Hope this helps anyone who has a similar problem of their 5th door randomly opening itself. Cheers