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Bought the male factory connector at dealership ($24.00) they kindda looked like I was from the moon...as they had never ever sold one before. guess Mercedes owners don't tow, splice the wires or use wireless.
I bought the Tekonsha P3,- one observation which is different from most cars I'm told, the diagnostics on these brake controllers don't work until you actually plug in a trailer. I'm guessing that has to do with the SAM module, which is part of the tow package.
Obviously you also don't want to mount a controller in the airbag area....
I've got the receiver and electrical trailer hook ups too, but I didn't know that was called the tow package. When I think tow package, I think transmission cooler, different rear end gears, tow haul button to change the transmission. I've never heard MB call it a tow package on the GLE. I thought it was something new.
I've got the receiver and electrical trailer hook ups too, but I didn't know that was called the tow package. When I think tow package, I think transmission cooler, different rear end gears, tow haul button to change the transmission. I've never heard MB call it a tow package on the GLE. I thought it was something new.
Your right! The option is called "trailer hitch" (Class III) and not a tow package.
I would imagine there might be an upgraded trans cooler (hopefully), but with a price tag of $575, the receiver and electronics must be all that are included.
Nookie - many thanks for the factual post - which will be a BIG help to those looking to install a wired brake controller...
Mercedes SUV's with factory "trailer hitch" package make OUTSTANDING recreational tow vehicles - just do forum search and READ outstanding comments from post from actual owner's who tow....
On MB's part - yes - MB dealer's are not as savvy as a pick-up-truck dealer when it comes to towing...
So you know - the hitch package gives you quite a bit more that "hitch" and "wiring" when it comes to towing...
Loke what ? Like ... ohh.. active trailer stabilization which I term "anti-see-saw"....
Is a 3rd party brake controller required to activate electric brake on a GLE with the tow package? While servicing my trailer (with electric brakes) to get ready for use this year, I discovered it appears the trailer brakes are not being activated by the GLE 7-pin connector and GLE brake pedal depress. All other GLE 7-pin functions (power/lights/signals) are working. At first I thought I had a trailer problem, but the emergency breakaway brake control does engage the trial electric brakes. But a simple test with trailer wheels jacked up in the air and depressing GLE brake pedal does not engage/stop trailer wheels from spinning. I was under the understanding that half-ish GLE brake pedal depress-ing would "power" the trailer brakes w/o any 3rd party brake controller?
GLE service time or is a brake controller required for this function?
I thought brake controller gave more options for electric trailer braking function, but was not a minimum requirement.
2017 AMG GLE 43 - Brilliant Blue / Black Napa Leather
Last edited by Kein Ersatz; 04-29-2018 at 06:17 AM.
An aftermarket trailer brake controller on the GLEs is required to activate electric trailer brakes. The problem is finding somebody to install one, unless you go the DYI route. The dealer where I purchased my ML 350 diesel in 2012 installed (for $600!) a TBC that I provided, but the work order had a long CYA note that Mercedes would not be responsible for any warranty-related issues. I've just taken delivery of a 2018 GLE, and two local dealers now refuse to have anything to do with any aftermarket items. They suggest trying an RV dealer, but I explored that for the ML and nobody would work on MBs, and I'm reluctant to let them.
The connection is actually quite simple, as there is a prewired connector bundled underneath the dash (or the carpet, some people say). I wanted the dealer to do it because the center console cubby is a nice place to mount a low profile Tekonsha controller but requires fishing the wiring through the back of the compartment. I don't want to mess with that myself.
One workaround is a Tekonsha radio-frequency controller that utilizes a remote that sends a signal to a module mounted on the trailer tongue to set the gain and make an emergency stop if required. No hard-wiring involved. The module itself controls the trailer brakes, drawing power from the standard 7-pin receptacle.
@Shrdlu, thank you so much for the reply and clarification. This was not obvious in the GLE Manual when I read the towing section. With the help of this thread and other references, I am all in for the DIY route to try hardwired first. I will post share my results/approach once installed.
I do not know if M-Benz is unique in this approach or if this is the common way a 7-pin SUV is sold (w/o brake pin activated) by other manufactures. I was under the impression, the '03 BMW X5 M I used before the GLE AMG as a tow vehicle with 7-pin connector & electric brakes on my trailer was activating the trailer brakes w/ half pedal depression, but I do not recall running a true wheels up test on the trailer. I was under the impression, in not electric brake activation for the factory wiring harness would be a 4/5-pin connector. Given the 7-pin "typical" blue wire is for brake activation.
Last edited by Kein Ersatz; 04-30-2018 at 11:02 AM.
Can't find the parts on that site. Partially because I'm not 100% sure what I'm looking for! Can you give part numbers or a link to the page it's on?!?
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.
So for my '17 AMG GLE the female plug above is not correct. The pins for the wires are correct. Part numbers seem to match, so not sure why the plugs didn't mate up correctly.
I ended up using chisel and Dremel (and tape & zip tie) to form a modified plug and pushed on to install the wire harness and P3. All seems to work fine in dry run (brakes on trailer now activate with manual P3 brake toggle and GLE brake pedal).
Will report back after next tow excursion with loaded trailer and final set up of P3 brake pressure.
Mounted P3 in console, had to extend P3 cable length to reach GLE plug. See photos of location. Some image/details below. Hope it helps others.
Trailex and '17 AMG GLE (above)
GLE Plug location, left upper corner of foot well. Remove 3 screws from path underside panel to reveal plug (above)
P3 wire harness routing inside of car console, requires some fishing. Use 1 wire to route then pull thru bare wires before making plug connection as plug will not fit thru behind console panel space. Had to extend length of P3 cable to GLE plug when using center console location. (above) This location allows P3 to be "held" (no bracket mounting) in cubby in GLE console. Leave slack in P3 cord as to pull out P3 to plug/unplug it as needed then push cord/plug back into cubby. Since the plug is always "live" be sure to not short out exposed plug ends when not plugged into P3 (cover with tape when not in use).
30amp fuse is located under rear passenger seat. Ask me how I know this :-P
Risking/tricky part. Need to make hole in console storage cubby (remove rubber pad to expose plastic). Note location of corner and bolt hole above for reference. 1/4" hole then enlarged with Dremel and smoothed edges to not chaff wires when moving in and out. I shrink-wrapped the last 4" of the cord to protect it. The cable goes in at an angle from right to left, 45 degrees-ish to the hole. Remember that when pulling and pushing.
This plug saga - was very frustrating. Ordered (online - factorymoparparts.com) the plug and pins from "thread" part numbers above. The part# female (ordered part) matches the part# (male) in the '17 AMG GLE brake controller. The pins do fit/work.
The 2 plugs do not match up in shape dimensions and nub. The yellow arrows point to a nub on the GLE male plug (orange arrow below) that doesn't align with female P3 plug slot. The GLE nub is too far towards the center compared to the female nub slot opening notch.
Furthermore those internal "ribs" on the female P3 plug (left/right) need to be removed (chisel) for the male rectangle to fit inside of the female. The (red arrows) external male GLE plug latch interferes with female P3 latch).
There has to be more to the part numbers. Maybe that secondary number 772-717.
In the end, I made the parts work with lots of mods.
Last edited by Kein Ersatz; 05-21-2018 at 10:36 AM.
E63 sold, 1972 911S, '58 Speedster, 2021 GLE 63S, Turbo 997, Aston Martin V8 Vantage 69 911 Hotrod
Hey Guys
Just read this thread and am wondering if any of you are in the LA, OC or San Diego area and know of an installer that can install my brake controller
in my 2013 ML63.
Reporting back after a season of successful towing. P3 is working well in the GLE ‘17. Towing is a breeze, pleanty of power, strong stopping, and no sway. Central Ohio to Watkins Glen was no worries for 9 hours each way.
hello to you,
I try to install one brake control on my ML350, 2014
I find the green connector on the driver side, but I don t have any power on it, connect my brake controller and no power, maybe some fuse ?
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.
Just wanted to say that this was an incredibly helpful thread, particularly the post above, in installing my Tekonsha brake controller in my 2017 GLS 450! Mercedes did indeed make fishing out this cable about as hard as it could possibly have been without actually gluing the cable to the firewall. The bit above about removing the trim piece on the left wall of the foot well was absolutely crucial, and I never would have been bold enough to try it otherwise. Fairly easy to pop out, and easy to pop back into place.
I had to laugh at everyone in these threads talking about the blank looks they are getting from the dealerships about towing, this was exactly my experience as well.
I’m not usually embarrassed to ask a question, but this might be an embarrassing question. I’m thinking about buying a 2017 GLE 350 with factory tow pkg to pull a trailer. Trailer plus load is about 2800 lbs. This thread, and a couple others on this forum, have been extremely informative. Thank you to all the contributors.
A couple of entries have said that a controller is required on a GLE, even when it has a factory to package, if you want to use the brakes on a braked trailer. I’m asking for confirmation on this. Without a controller, like the P3, the GLE’s towing features will not be able to engage/control the trailer’s brakes. Period.
Thanks in advance.
Last edited by Phillipangelo; 11-20-2020 at 09:46 PM.
Actually a good question. It is the standard and easiest way to activate the electric brakes on a typical trailer. Some how you have o provide a graduated "strength" signal to the trailer electric brakes, that complex feature is not part of the GLE wiring.
The Prodigy allows for adjusting to the type of trailer (weight) being towed. There is no one size fits all solution that MB could make "standard" so you need to add that to the installation yourself.
Electric brakes are the best/safest trailer option, but mechanical surge brakes are another less effective path that do not require a P3 to operate (think U-Haul, etc).
07-10-2017, 08:28 PM
