I've been having an issue with buzzing and rattling on my 2014 Overland. The sound was coming from the A-pillar area somewhere between the OBDII receptacle and the tweeter. It manifested usually while cruising between 40-60mph on relatively smooth but vibrating roads. It seemed to be getting worse.
It was driving me crazy for a while but one day I was randomly tapping the exterior of the car when I heard a reverberation at the rear of the front left fender directly in front of the driver's door.
This is the area I tapped:
I found that the issue was a connection between the exterior fender panel and the body of the car. There is a little bolt bolted from inside that needed to be tightened down.
Here is a picture of the bolt, you can see the threaded end of the bolt sticking out:
To tighten, you'll need to pop off four (or five) plastic body fasteners. These are the two piece type which require you to carefully remove the middle pin then the fastener. I used a plastic body pry tool which came in handy.
Once it's open enough (you really don't have to take the whole thing off), move it off to one side and stick your hand in the slot. You'll just have to feel around for the bolt. I came back around and looked at the end of the bolt as a reference. It is a tough reach, though, and I'm 6'2" so it may be more difficult with shorter arms. There's just enough room to get a small 1/4" ratchet in there and tighten the bolt. The bolt itself is a 10mm hex head. The space is tight though so you'll definitely need a small 1/4" ratchet. I was barely able to get 2-3 clicks on my ~8" wrench.