I had a heavy TV in my passenger seat the other day. I took an off ramp kinda fast and the interior lights started flashing and car started "ding"ing. That ding you get like when gas is low. Only did it for a couple seconds.
Then the other day I had my friend in my passenger seat, and he's a heavy dude. It started doing it again randomly when I was driving.

Anyone know what's up? Thanks.

 

Car thinks your door is open. It's a bad sensor (in the door I think).

There are threads on it that identify the failed parts. Try searching "Door Open" or "Door Sensor" or Door Open Sensor.

 

My man! Thanks! Love this forum.

 

The door sensor cover may have been removed or the contact area, where it pushest the sensor may also be worn. Check that first. Good luck.

 

Also make sure your door is aligned. Mine was doing the same thing. After adjusting the striker plate inwards a couple of mm everything was fine.