When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Here's my dash cam install for a GLA35. Figure it'd be the same for the other models. I installed a Viofo mini and just picked up a general hardwire kit on Amazon. The Youtube video link tells most of the story. The fuse diagram that can be found in the engine compartment fuse box isn't complete. The empty fuse that I used wasn't listed in the diagram so I have no idea what it was for, but it turns on and off with the car.
When I pulled the trim off the pillar, the metal clip released from the trim pillar. Had to pull the metal clip around and reattach it to the trim before reinstalling it.