Firewall access
 

I'm trying to install a front camera on the GL550, but I can't seem to find anywhere to run the rca cable from the firewall into the cabin...any of you guys done this before or know where I can access the cabin from the firewall? Thanks in advance!

I haven't done it on this vehicle, but I've gone through firewalls on other vehicles. The easiest place I have found in the past is in the brake pedal area by drilling a hole. A rubber grommet and silicone fills the hole nicely. But, again, haven't done it on the GL - but maybe you could look in that area and see what's up.

Like the previous post, I've never done it on this vehicle. But I've done it on plenty of others. There are always several since you have to get electrical power through. I'm not a fan of drilling especially if you need to only get a small wire through for a camera. There is almost certainly a plug behind the glove box where you can push a wire through with the existing wires.

Ah, but, is that "plug" not ALREADY a hole? :) I'm betting I'm as capable as MB at drilling a hole and protecting the cut edge... both from corrosion and sharpness. :)

But, yeah, if you can find an unused hole (or one that currently has something in it and you sneak another wire through), then that makes the most sense.