Trailer brake contol module
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?
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.
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.
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.
Wayne
"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.
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?
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.
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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.
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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.





I don't have the trailer plug connection wiring handy. I do know socket pin 4 is permanent trailer power (up to 240w).
Last edited by GregW / Oregon; May 26, 2012 at 10:52 AM.
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.
Last edited by Chetter0404; May 30, 2012 at 12:35 PM.
-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.
Last edited by James Courtney; Apr 10, 2014 at 10:02 AM. Reason: slightly better punctuation/grammar, my bar is low
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.
Last edited by DUTCH; Apr 11, 2014 at 06:20 AM.
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?
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!!!
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.
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!!!
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.
Last edited by DUTCH; Apr 11, 2014 at 02:03 PM.


