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Has anyone installed a hard wired trailer brake controller yet. I would like to know if the wiring on the GL is still available to connect to the controller wiring, like older models under the driver foot well? Also where to install the controller so that it does not interfere with the knee airbag deployment or cause any other potential issue. My 2014 ML has the controller under the dash above the driver footwell and can the 2020 models do the same? I don't like the wireless version brake controllers for several reasons. I will post the same thread on the GLS X167 forum as the results should be the same for both vehicles.
Has anyone installed a hard wired trailer brake controller yet. I would like to know if the wiring on the GL is still available to connect to the controller wiring, like older models under the driver foot well? Also where to install the controller so that it does not interfere with the knee airbag deployment or cause any other potential issue. My 2014 ML has the controller under the dash above the driver footwell and can the 2020 models do the same? I don't like the wireless version brake controllers for several reasons. I will post the same thread on the GLS X167 forum as the results should be the same for both vehicles.
Have you inquired with you dealer's service department? Since the maximum towing load is only available with a braked trailer it seems they would have a way to accommodate the control.
Last edited by GregW / Oregon; 11-16-2019 at 12:32 PM.
They are not helpful at all. Every time I ask about installing something not provided from the factory I get the same story they can't recommend or authorize non MB approved parts and accessories and won't be liable etc. MB Canada Customer service is even worse. Since i already have a controller I want to install myself.
They are not helpful at all. Every time I ask about installing something not provided from the factory I get the same story they can't recommend or authorize non MB approved parts and accessories and won't be liable etc. MB Canada Customer service is even worse. Since i already have a controller I want to install myself.
Can you get help from the controller manufacturer? I have submitted the question to MBUSA - likely they will not be any help either.
Last edited by GregW / Oregon; 11-16-2019 at 12:40 PM.
Not sure how much help this will be, but I had to install an electric brake controller on my 2017 GLS. I took the controller and installation schematics to the dealer and they had one of their best technicians come out and take a look at it. He said he could and when I picked it up the next day he had done an excellent job. The wiring is indeed accessible above the driver foot-well and he routed it behind the dash board and out the recessed pocket in the middle of the console (where the wireless phone charger is now). When the brake controller isn't needed I can unplug it and hide the connector in a small hole beneath the rubber flap covering the pocket, stow the controller in the glove box. Damn nice job and I let him know it. The newer model with the wireless charger in that pocket may complicate or prevent this approach. I have a 2020 GLS on order but wont take delivery of it for another month so can't speak first hand with any suggestions on that design yet. Seems service experience varies a lot with dealers. How many dealers within driving range can you ask?
I recalled a few more details from when I had this done 3 years ago. Like you I didn't want to interfere with anything within the foot-well area, including knees, etc. I also didn't want to "bouger" up the appearance of a nice vehicle. When I spoke to the tech, my suggestion was to attach a cable to the pre-installed wiring under the dashboard right above the foot-well that also had the proper connector for my controller on the other end and then run enough length to reach the console pocket. Then when I used it I could make the connection and lay the controller in pocket. When not in use I could disconnect it and hide and secure the cable above the foot-well with a Velcro fastener and stow the controller in the glove box. The tech ran with that idea and went one step further by completely hiding the wire with the connector on it beneath the dashboard and exiting in a small hole hidden within the pocket beneath the removable rubber insert. With a wireless phone charger now in that pocket, the original idea of running a movable wire harness with the controller connector may still work. Tuck and hide the wire harness away within the foot well area when not in use.
Has anyone installed a hard wired trailer brake controller yet. I would like to know if the wiring on the GL[E] is still available to connect to the controller wiring, like older models under the driver foot well? Also where to install the controller so that it does not interfere with the knee airbag deployment or cause any other potential issue. My 2014 ML has the controller under the dash above the driver footwell and can the 2020 models do the same? I don't like the wireless version brake controllers for several reasons. I will post the same thread on the GLS X167 forum as the results should be the same for both vehicles.
Here is the response from MBUSA. They actually answered a question! See attached instruction sheet.
"Thank you for your contact to MBUSA.
Review of records show your VIN has Code 550, hitch installed, therefore you would have the wiring needed for installation of an aftermarket brake controller. The dealership parts team should have the green connector/pins.
There will be a connector located near the trailer hitch where the trailer lighting and brake harness plugs into the vehicle.
Thank you Greg, for sharing your wealth of knowledge on this forum. You have excellent contacts too and must be high priority for MBUSA to get such quick answers! I am lucky to hear back from MB Canada in less than a week, if at all.
Thank you Greg, for sharing your wealth of knowledge on this forum. You have excellent contacts too and must be high priority for MBUSA to get such quick answers! I am lucky to hear back from MB Canada in less than a week, if at all.
Well, thanks, but I have no special "in" with MBUSA. Emailing though the Owner's link usually gets a response, but seldom one that really answers the question. This is an eception.
I have seen many positive reviews of the Curt Echo wireless brake controller. It plugs in to the rear MB RV style plug and provides full electric brake control without further wiring. It uses a multi axis accelerometer. I have confirmed with Curt manufacturing the product will work in my 2020 GLE 450 (where the RV plug is angled upward about 45 degrees). My only concern is how low the controller and cables will be to the ground when hooked up.
I have seen many positive reviews of the Curt Echo wireless brake controller. It plugs in to the rear MB RV style plug and provides full electric brake control without further wiring. It uses a multi axis accelerometer. I have confirmed with Curt manufacturing the product will work in my 2020 GLE 450 (where the RV plug is angled upward about 45 degrees). My only concern is how low the controller and cables will be to the ground when hooked up.
The Curt is long and rigid and will extend far enough towards the ground because of the 45 degree angle, I fear it could get damaged and I would be stranded. I have not tried it but read there is a slight delay. Also comments from an industry towing expert (Andrew Thompson Can-Am RV) on the Airstream forum ,"The Curt control is not really close to the Prodigy in braking performance. It is simply time actuated instead of inertia activated." Also when I tested it an incoming phone call interrupted the brake activation". Tekonsha Prodigy RF controller is better with excellent reviews for just over $400CAN but I already have a Tekonsha Prodigy 2 and like the security of the hard wire version.
I am new to MB and this forum. I recently purchased a 2020 GLE 350. I have been towing a 4700# travel trailer with a Toyota Highlander and didn't want a truck or monster SUV. I was looking for some more oomph and was seduced by the 7200# tow rating. It's hard to believe that the GLE can do it with a smaller 4 cylinder engine ( I know the torque is higher and at lower RPM vs the Highlander). I won't know for sure until I see it myself in the spring. Can anyone out there speak to the 7200# claim?
Meanwhile, I need to get ready for spring. My local MB dealer is no help at all regarding towing and installing a brake controller. I would like to use a Tekonsha P3. They have a plug and play adapter for earlier GLEs (#90195) Does anybody know if this adapter will work for a 2020?
Traditional 7 pin trailer wiring includes a hot 12V pin to power the trailer and possibly charge the trailer batteries while underway. Page 271 of the owner's manual says, "Do not use vehicle's power supply to charge the trailer battery". The Local MB service manager thought that shouldn't be a problem. Any thoughts?
A tester shows the 12V pin is dead. The service manager said that I would need to run a wire from the battery to the trailer connector. For a vehicle that's touted as a robust tow vehicle, this seems like MB has dropped the ball.
I have always regarded tow ratings as the manufacture’s comments on how much weight the vehicle can get moving and stop without any components failing due to stress prematurely. It is not a comment that the GLE 350 driveline will do a good job of propelling your approx 9000 Pounds.
Not exactly the same vehicle changes as you but similar questions. I moved from a Toyota Land Cruiser with a truck frame and V8 to a GLS with a unibody chassis and a V6 for more comfort, better gas mileage, etc. I was hesitant about changing from a truck frame to a unibody chassis but after some research learned that in the past 10+ years computer aided engineering design has advanced significantly and enabled manufacturers to improve the strength to weight ratio of unibody chassis significantly. For extreme loads steel truck frames are still superior but in the range of recreational boats and campers unibody frames are much lighter and now very strong. Engine selection depends on terrain - steep mountains versus flat. A simple method that I also found with some research is to approximate the equivalent towing capacity of the vehicles is by dividing the engine horsepower by the total weight of the tow vehicle and the trailer combined. (highlander HP)/(highlander weight + trailer) then calculate it for your new vehicle (GLE HP)/(GLE weight + trailer). Then take the ratio of those two numbers to estimate their percentage towing equivalence. You can do the same calculations using engine torque instead of HP to get the complete comparison. For me, the GLS was much lighter and even with a V6 still had about 97% of the towing capacity in regards to both HP and torque. My towing experience with the GLS and its V6 around the hills of Pittsburgh has confirmed that. No regrets. Can't comment on charging your trailer battery with your vehicle although I would think it would be fused to prevent any overloading of it. Not sure if the manual is concerned with possibly draining your vehicle battery.
Thanks Margaretta and Doug. I am still looking for info on brake controller installation (plug and play compatibility for Tekonsha P3 in 2020 GLE 350}. Also any insight regarding the “hot” 12 volt pin on factory 7 pin connector per my post above. Happy Holidays.
I am new to MB and this forum. I recently purchased a 2020 GLE 350. I have been towing a 4700# travel trailer with a Toyota Highlander and didn't want a truck or monster SUV. I was looking for some more oomph and was seduced by the 7200# tow rating. It's hard to believe that the GLE can do it with a smaller 4 cylinder engine ( I know the torque is higher and at lower RPM vs the Highlander). I won't know for sure until I see it myself in the spring. Can anyone out there speak to the 7200# claim?
Meanwhile, I need to get ready for spring. My local MB dealer is no help at all regarding towing and installing a brake controller. I would like to use a Tekonsha P3. They have a plug and play adapter for earlier GLEs (#90195) Does anybody know if this adapter will work for a 2020?
Traditional 7 pin trailer wiring includes a hot 12V pin to power the trailer and possibly charge the trailer batteries while underway. Page 271 of the owner's manual says, "Do not use vehicle's power supply to charge the trailer battery". The Local MB service manager thought that shouldn't be a problem. Any thoughts?
A tester shows the 12V pin is dead. The service manager said that I would need to run a wire from the battery to the trailer connector. For a vehicle that's touted as a robust tow vehicle, this seems like MB has dropped the ball.
Any advice would be welcome.
There are only 4 wires to connect to the brake controller. I assume you have the factory option for the trailer hitch so you will also have the 7 pin connector on the hitch and there will be a 4 wire connector for the brake controller in the driver's footwell under the plastic panel. You can eliminate the connector and crimp the wires directly. You don't need the 12v to feed the trailer at the 7 pin connector unless you want to charge the trailer battery. I have never needed it and if it was connected the trailer could drain the car battery when parked if the 7 pin is connected. This thread may be helpful https://mbworld.org/forums/gls-class...tallation.html I also attached a document from the old model which I understand is still valid for the newer model.
Last edited by marchgroupinc; 04-12-2020 at 10:36 AM.
Reason: new info. update
Thanks for trying but not what I needed. That was for a brake controller. Mine is about trailer wireless backup cameras not getting enough voltage. In fact I am using that brake controller and it works great.
I am possting this on the GLE forum too because the wiring and trailer equipment are identical.
I finally got my GLS the other day 363 days after I ordered it. I confirmed the wiring is there in the footwell for the Trailer Brake Controller and wired my Prodigy 2 exactly the same way as my ML350. Same color wires also. There is space for the controller in the footwell so it does not interfere with the knee airbag. The airbag is in the middle of the footwell and the panel covering the airbag is only approximately 10 inches wide so you can mount the controller to the right or left under the dash.
My current problem is there is no power running the the red wire with blue stripe from the GLS which powers the controller. I checked all the fuses designated for "trailer hitching" #450, 452, 453, 454 which are fine but there is one of the fuses #436 which is missing the holder completely at location 436 in the rear cargo fuse panel - see pic of pencil pointing to where it should be. I don't know if this fuse is for the red wire with blue stripe. Maybe there is another issue? I also connected the GLS to my trailer and the lights work but no power to the brakes.
Does anyone have a hard wired brake controller connected to the GLS wiring under the dash? Do the euro models use that fuse #436 - maybe its for the electrically retractable hitch? I can't get an answer from my dealer because they are closed until further notice. The fuse holder at location 436 is not there - what is it for specifically?
Any GLE or GLS owners out there with the trailer hitch option that can tell me if they have a fuse in location 436? Please specify if you are North American or Euro/UK spec. The electronic retractable hitch is not available in North America and may be the reason my Canadian GLS doesn't have a fuse in location 436.
Any GLE or GLS owners out there with the trailer hitch option that can tell me if they have a fuse in location 436? Please specify if you are North American or Euro/UK spec. The electronic retractable hitch is not available in North America and may be the reason my Canadian GLS doesn't have a fuse in location 436.
I have the factory hitch, and there is no fuse in that location.
For anyone following this thread I now have my hard wired Tekonsha Prodigy 2 brake controller working. I took it to the dealer this week because I could not get power from the factory 4 pin plug under the dash for the brake controller. Despite my prior checking of fuses the dealer told me the problem was just a blown fuse. Bottom line you can use the 4 pin plug in the 167 like the 166 version before. The trailer brake controller however works differently in the X167.
I took the trailer brake controller out of a 2014 Mercedes ML350 W166 and put it in a 2020 Mercedes GLS580 X167. I discovered the red wire also does not get power when the brake is applied on the GLS580 unless the 7 pin trailer plug is connected. That was not the case with the ML350 which always woke up the P2 when the brake pedal was pushed trailer connected or not. The GLS580 does not wake up the P2 unless the trailer is connected or the manual brake lever is activated. FYI on Mercedes the factory wires supplied under the dash for the brake controller the brake (red) wire from the controller connects to the black wire with red stripe from the factory plug and must be connected to the trailer to get power.
Last edited by marchgroupinc; 06-18-2020 at 08:33 AM.
Reason: new additional info.
For anyone following this thread I now have my hard wired Tekonsha Prodigy 2 brake controller working. I took it to the dealer this week because I could not get power from the factory 4 pin plug under the dash for the brake controller. Despite my prior checking of fuses the dealer told me the problem was just a blown fuse. Bottom line you can use the 4 pin plug in the 167 like the 166 version before. The trailer brake controller however works differently in the X167.
I took the trailer brake controller out of a 2014 Mercedes ML350 W166 and put it in a 2020 Mercedes GLS580 X167. I discovered the red wire also does not get power when the brake is applied on the GLS580 unless the 7 pin trailer plug is connected. That was not the case with the ML350 which always woke up the P2 when the brake pedal was pushed trailer connected or not. The GLS580 does not wake up the P2 unless the trailer is connected or the manual brake lever is activated. FYI on Mercedes the factory wires supplied under the dash for the brake controller the brake (red) wire from the controller connects to the black wire with red stripe from the factory plug and must be connected to the trailer to get power.
I recently got a GLS580 (I am in Canada) and it came with the factory hitch. I was at a RV Trailer dealer yesterday, was going to try to tow by using Curt Echo . The Echo didn't get any power and I am wondering if it is the same issue you had that the Manual Park Brake needs to be on for it to receive power. The unit briefly turned on for 2-3 seconds when I connected the trailer's 7-way connector to the Echo but went offline again.
Did you had to install any fuse or anything at that #436 spot? Mine looked identical to yours (without any fuse).
Not sure how much help this will be, but I had to install an electric brake controller on my 2017 GLS. I took the controller and installation schematics to the dealer and they had one of their best technicians come out and take a look at it. He said he could and when I picked it up the next day he had done an excellent job. The wiring is indeed accessible above the driver foot-well and he routed it behind the dash board and out the recessed pocket in the middle of the console (where the wireless phone charger is now). When the brake controller isn't needed I can unplug it and hide the connector in a small hole beneath the rubber flap covering the pocket, stow the controller in the glove box. Damn nice job and I let him know it. The newer model with the wireless charger in that pocket may complicate or prevent this approach. I have a 2020 GLS on order but wont take delivery of it for another month so can't speak first hand with any suggestions on that design yet. Seems service experience varies a lot with dealers. How many dealers within driving range can you ask?
hi, I have a 2017 GLS 450 that doesn’t have the factory tow package, and I’m trying to get the OEM package retrofitted. Called a couple of dealers and they both told me nothing is pulling up for them when they run my VIN (I assume through WIS or XENTRY). I think I really need to do what you did there, basically bring the parts and instructions to them. Did your 2017 have the factory installed tow package? Could you share the instructions for your break controller? Thanks!
hi, I have a 2017 GLS 450 that doesn’t have the factory tow package, and I’m trying to get the OEM package retrofitted. Called a couple of dealers and they both told me nothing is pulling up for them when they run my VIN (I assume through WIS or XENTRY). I think I really need to do what you did there, basically bring the parts and instructions to them. Did your 2017 have the factory installed tow package? Could you share the instructions for your break controller? Thanks!
Both my 2017 and 2020 GLS's came with the tow packages. Between vehicles I also traded in the old boat for a new one and its trailer has surge brakes so a controller isn't necessary now. To help the future owner of my 2017 I left the controller and schematics in the vehicle at trade in (MB dealer appreciated it also). Sorry
11-16-2019, 10:29 AM
