Locating wiring for brake controller on GLE w/factory Trailer Hitch (opt 550)
11-04-2019, 03:52 PM
#1
Locating wiring for brake controller on GLE w/factory Trailer Hitch (opt 550)
Hello all....after reading several good threads about towing with the GLE and about installing the aftermarket brake controller, I jumped in to install on mine. I was confused when the male end of the factory harness was not where I expected it to be. All of the posts online and the instructions included with the Tekonsha OEM wiring harness indicated it should be just behind the brake pedal under the carpet. I could not locate the green end anywhere and was about to conclude I would be splicing into the brake wires. Finally I found the message below from Bob68 buried in one of the installation threads. Yes, the wire harness was there, but deep under the carpet almost at the base of the gas pedal. Unlike Bob, I did not have to pull the door sill trim, as I was willing to tug a little bit on the wires going towards the gas pedal based on his description.
I hope this makes it easier for someone else to find! Thanks Bob68
It was a struggle to find the end of the factory supplied trailer brake controller wiring on my 2017 GLS. It was even more difficult to find good information on the internet and impossible to get information from my dealer!
There is a 4 wire bundle: Larger red/white stripe and yellow/red stripe and smaller black/white stripe and brown. They are intermittently wrapped in a black cloth wrapper. There was a piece of white masking tape holding them up above the carpet.
The wire enters along the left side of the foot well and takes a path up to the top edge of the carpet and arches over to an attachment snap behind and to the right of the brake pedal assembly on the firewall. It then dives down very far under the carpet toward the gas pedal. This was much more difficult than it needed to be which is frustrating.
I was finally able to find the end by removing the trim that goes on the door sill and up to the rear of the foot well. It simply snaps off. This allowed me to pull up just enough on the carpet to free the end of the connector. This was not easy. Not being certain that the connector was there, I was afraid to pull too hard on the wire.
The path of the wire approximately follows the dashed red line on the attached document, but this is from older models.
I found this article on another site. The wires on my '18 GLE Coupe were exactly where the article says. I pulled the carpet by the brake pedal back and there they were.
Pulled them out and Voila.
There is a 4 wire bundle: Larger red/white stripe and yellow/red stripe and smaller black/white stripe and brown. They are intermittently wrapped in a black cloth wrapper. There was a piece of white masking tape holding them up above the carpet.
The wire enters along the left side of the foot well and takes a path up to the top edge of the carpet and arches over to an attachment snap behind and to the right of the brake pedal assembly on the firewall. It then dives down very far under the carpet toward the gas pedal. This was much more difficult than it needed to be which is frustrating.
I was finally able to find the end by removing the trim that goes on the door sill and up to the rear of the foot well. It simply snaps off. This allowed me to pull up just enough on the carpet to free the end of the connector. This was not easy. Not being certain that the connector was there, I was afraid to pull too hard on the wire.
The path of the wire approximately follows the dashed red line on the attached document, but this is from older models.
I found this article on another site. The wires on my '18 GLE Coupe were exactly where the article says. I pulled the carpet by the brake pedal back and there they were.
Pulled them out and Voila.
