We got a new GLE and wanted to tow our camper. We got the tow package (550) and wanted to add a brake controller to accommodate our camper's electric brakes. We had a Tekonsha Primus from our last car and we bought the Tekonsha cable for Mercedes on Amazon.

It's plug and play but holy smokes is it tough to find the elusive green plug to connect the brake controller.

FYI - it's way up under the dash above the brake pedal and to the left. You have to remove the dash panel above the driver's foot well. Two screws, a push clip, unplug the speaker, pop out the light, unscrew the hood release and slide it through, slide the clip on the back of the obd connector to remove. You'll see the green plug up above where old cars had their parking brake.

We went nuts removing the sill plate and pulling the carpet back looking for the connector under the carpet. It wasn't until I'd fully removed the bottom of the dash that the green plug became visible. I imagine you could feel around for it once the panel was loose but honestly it was hard to see even when with the panel out. It was nested in the vertical cable runs on the far left (driver's) side.

The plug was bare just floating around up there. No black cloth wrap or masking tape as I've seen in earlier model posts.

Apparently this connector is only present if you have the factory tow package. No worries though. If you don't have the tow package you can still hand-wire a brake controller. It's a lot of research/work and the tow capacity is less weight but still possible. Good luck!!!