Jim Brady

Getting ready to start towing my race car in another month.

I'm going to need a electronic brake control module and wonder if any members on the forum have installed one on a 2012 ML 350 bluetec?

If so is it a diy?

Shrdlu

I have a 2012 BlueTEC on order and will be towing an enclosed cargo trailer. The local dealer has no info on integrating a trailer brake controller for the 2012s. Earlier models had a connector up inside the driver's side footwell, and there is a MB document that tells how to wire a controller to it.

Instead, I am going to try a Prodigy RF controller. This controller is screwed to the trailer tongue, bypassing the ML harness. Basically, you plug one end into the vehicle and the other into the trailer. A hand-held, radio-frequency remote is used to adjust the trailer braking force. Prodigy said the unit is FCC approved and should not interfere with the ML's multitude of sensors. It is around $300 though.

Jim Brady

Shrdlu,
Thanks for the reply. Hadn't thought about the RF system good find. I've had several Prodigy's in other SUV, and where most american Mfgs are usuually a dyi or plug and play mercedes and porsche you have to carve into the wiring system for brake controler.

venchka

It would be nice if M-B would deliver a complete towing package. The least they could do is offer a wiring receptacle for the brake controller. They really are clueless.

Wayne

tgk

This is what I received from MB when I asked the same question about brake controller installation ease on my new 350 BlueTec:

"2012 M-Class Electric Brake Controller Installation

Below is a picture of the X58/28 connector for the customer supplied electric brake controller. Look under the carpet in the driver footwell area for the harness. Also attached are the X58/28 connector pinouts. All customer connections are made at this point.

Connector X58/11, located near the trailer hitch, is where the trailer harness plugs in to the vehicle."

Will try to attach pictures (first post here...) Hope it helps, but the RF seems like a good way to go. Thx.

Shrdlu

Has anybody successfully installed a trailer brake controller on their 2012 ML50?

Local MB dealer says, according to the factory, a controller is "not recommended" at this time because an installation kit is not yet available.

In an attempt to bypass the vehicle electronics, I attempted to install a Prodigy RF controller (described earlier in this thread) but could not get the remote to "pair" with the controller. Prodigy says they have found that some newer MBs do not have the 12-volt power supply wired to the trailer plug receptacle

I note the earlier post with thumbnails concerning 2012 installations. Has anyone gone this route?

vonzellen

I have a new 2012 ML350 and wanted to install a brake controller with out the module being screwed into the dash or elsewhere. I thought the Prodigy RF would be great.

I got it and had trouble installing it. But, techs walked me through it and now it does work fine.

The trick is to plug you cable from your controller into another car or truck that supplies the 12volt power. Once that is done the unit will "Pair" and you will be set. Then you plug in back into the ML350.

I just backed my truck up--plugged in and it paired just fine.

Chetter0404

I have a 2009 ML320 Blue Tec with the factory installed trailer package. Three years ago I hand my RV dealer install a Drawtite braker controller and it works fine. I am taking possession of a 2012 ML350 Blue Tec tomorrow and need to switch over the controller. To see if it was a DIY job I unscrewed the panel under the dash. The MB wiring harness had a green qwik connect on it, however the controller by-passed it and was spliced into the wires. I assume this was because the installer did not have the matching qwik connect. I also noted that the colour coding on the wires did not match up. I found a schematic for the controller wiring but I cannot find a schematic for the MB wiring. Any idea where I could find this?

BTW: MB wanted $800.00 to re and re the controller. I paid around $550.00 three years ago for my hitch, brake controller and instalation.

Shrdlu

An earlier post in this thread showed the pinouts ( wire colors and functions) for the MB brake controller receptacle.

Chetter0404

I'm sorry. I may be missing something, but I reviewed all previous posts and cannot find the schematics.

GregW / Oregon

Not schematics, but wire colors and functions in the last pic on post #5.

Chetter0404

The three pictures show me where the harness is, what the connection plug looks like and the trailer connection at the back. Again, am I missing something? No where in that post do I see a description of the colour of the wires or what they mean.

There are four wires on my controller

Black - Battery (+)
White - Ground (-)
Red - Stoplight
Blue - Brake

On my 2009 ML320 these were hardwired as follows:

Black - Red/Blue
White - Brown
Red - Black/Red
Blue - Yellow/Red

I'm picking up the new car today and once I get it home I plan to look for the harness and see if MB uses the same colour coding for the wires. If they do, I'm still not really comfortable assuming that they perform the same function. I guess worse case scenario is I fry my controller and/or blow a fuse in the car although the prospect of doing more severe damage to the vehicle is making me very reticent about making the above assumption. A wiring schematic would be very helpful.

If anyone has a brake controller installed on a 2012 ML 350 and can take a look at the connection I would be very grateful.

GregW / Oregon

There is a fourth picture for the controller wiring:



I don't have the trailer plug connection wiring handy. I do know socket pin 4 is permanent trailer power (up to 240w).

Chetter0404

Thanks. I must have looked at that post a dozen times and I could swear there were only three pics.

Sorry.

Chetter0404

I have been trying to get my brake controller installed in my 2012 ML350 and I am nothing short of frustrated with MB to the point where I am thinking of doing it myself. During my last call to MB Service I was told "we will have to see if we can find a plug that matches to connect up the controller to the factory wiring harness" which tells me that they will likely just hard wire it. They also told me that there was nothing that needed to be done to the rear SAM unit. They are still telling me it's 3 hours.

I am completely satisfied, thanks to the previous posts and from observing the connections on my old ML before disconnecting it, that I can connect it up properly. My only concern is that the instructions say to disconnect the (-) battery terminal connection before proceeding. This make perfect sense to me as a brief touch of the wrong wires and poof. However, given the complexity of the computers etc in cars these days are there any concerns about disconnecting the battery terminal?

The last time I worked on my own car was 1976. I could open the hood, crawl inside and close it behind me. Would appreciate any advice, caution or outright "do not do it" from you DIY'ers.

Chetter0404

Update: Installed the brake controller myself on the weekend.

-Removed the plastic panel under the dash
-Found the wiring harness behind the carpet
-Disconnected the battery (under the passenger seat BTW)
-Snipped off the qwik connect
-Connected the wires according to the diagram posted above
-Put solder on each connection and wrapped in electrical tape
-Replaced the plastic panel
-Connected controller, reconnected the battery and presto!
Took me about an 1 1/2 hours and that included a 15 minute search for the battery location. Much better than MB's 3 hour estimate at $80.00 an hour plus parts and taxes.

James Courtney

After speaking with two dealers who didn't really know (at least one of which admitted NO ONE had ever asked about electronic brakes before - on a vehicle rated to tow 7200 lb!!), I used MBUSA's IM support feature yesterday to inquire about installation of brake controllers in my fiancee's 2014 ML350 Bluetec. They didn't quite understand at first but, with further explanation, asked around and dug up a document supposedly applicable to the most recent iteration of the ML350 (166/X166). It appears the doc may also apply to the GL and is relevant if the vehicle was sold with code 550 (factory trailering package). I've attached the 1-page PDF in the hopes it'll help the next person in their quest to solve this unnecessarily obfuscated riddle. I'll report back in a few weeks on the accuracy of this document and my success in installing a controller, if any.

DUTCH

On my 2014 ML350BTC, that socket was not under the carpet. It was taped to the supply wires for the OOBD2 socket right at the back edge of the under dash plastic panel.

No need to remove the carpet. Just feel around where the OBD2 supply wires are located. A small piece of masking tape holds the electric brake controller wires and socket within easy reach.

The real trick is where to place the controller itself. You can't attach it to the panel below the steering wheel, because there's an air bag there. The best place I found was in the small cubby just below the A/C controls. Just hold it in place with bean bags or foam squares.

James Courtney

Thanks Dutch, very helpful. Did you or anyone else figure out where to get an "X58/28" connector I could use to attach to the pigtails of my controllers harness and make a proper adapter?

DUTCH

Your MB dealer can get the connector and the contact pins. The correct MB part numbers are in this older attached TB.

MBStream

All

I did not see any discussion around the rear SAM in this discussion (sorry if I missed it!).

Does anyone know if the rear SAM needs replaced or updated to function properly with hitch and ebrake wiring updates.

I have seen a few posts where they say the rear SAM functions with the transmission, and w/o this update you will have issues when towing that could damage the transmission.

Thoughts on this?

James Courtney

My understanding (untested as of just yet) is that if your vehicle came with the factory towing option ("Code 550") that the rear SAM should be properly configured/included/whatever and it SHOULD simply be a matter of plugging in the controller. Wouldn't bet my or anyone elses life on this though and I'll report back in a couple of weeks once I've actually gotten something successfully installed.

MBStream

James

I don't think I have the 550 towing option, is there an easy way to determine this? Would they actually provide a towing package w/o the hitch as a part of the package?
Also, that brings up a separate question.
Is it safe to tow a small AirStream (4500lb) w/o the factory towing package?

Thanks for the help and quick replies all!!!

MBStream

I did find this on the MB site when you "build" a new car.
Looks like ALL ML class are ready tow, the "trailer hitch" just provides wiring and hitch setup. This leads me to believe their is no SAM or transmission cooling update needed.
Can anyone confirm this?

This is straight from the MB site.
Trailer hitch kit
With the optional trailer hitch, an M-Class can tow up to 7,200 lbs (6,600 lbs for ML350 with rear-wheel drive). The hitch option includes the wiring harnesses for the trailer lights and brakes, while every M-Class is already equipped to handle the rigors of towing on the engine, cooling system and transmission. Standard Trailer Stablity Assist helps keep trailer sway under control.

DUTCH

If you want to send me your VIN, I can look to see if it came from the factory with the towing package.

I would not pull 4500 lbs without a brake controller.

You will not be pre-wired for the brake controller unless your car was equipped with the towing package from the factory. See the large letter and underlined statement at the bottom of this attachment from MBUSA.

I would not be surprised if it also does not include the towing SAM; but this is just speculation on my part. You might want to contact MB's information line to find out. My 2014 ML350BTC, which has the 550 towing package, shows a towing specific rear SAM in the EPC. Your VIN would enable me to see whether yours has it or not.