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I'm installing a factory hitch and need some assistance with the wiring harness.
There are two connections i need help with. On the brake control harness there are 2 connections, one is a small black/white wire with a pin connector and another small female two pin connector w/ brown and brown/red wires. was wondering if anyone knows where they connect or can send me wiring diagram.
Also on the controller,what wires connect to the blue connector?
Installed my facory OE hitch kit last weekend,labor intensive but got it done.
Took to dealership for recoding,no sam change required. It even added a
"SUV connected to a trailer" icon displayed when reverse camera is activated
and changes camera angle down for connecting to trailer tongue.
Total cost: 870.00 for hitch kit, 20.00 for adblue tank bracket, 236.00 for dealer recode, 1 1/2 hr labor.
Any chance you have part numbers for the harness and the adblue bracket? I've found an OEM hitch for our 2014 ML350. If I can get the PNs for the other components it would really help.
Did you have to add any fuses and if so in which locations? I have a '14 ML with a factory hitch. I don't seem to have power to the center pin which is the power for back up lights. I am wondering if I have a fuse missing. BTW a 7 to 4 pin adapter does power the lights on my brother's trailer.
I had to install 6 fuses. Fuse diagram with car just says
Trailer hitch: f 101 20a. f 111 15a f 115 5a f 126 15a f 128 20a. f 130 20a
Hope this helps
Jerry
Went at it again with all good fuses in those slots, but still no reverse power at the hitch. I ordered a 7 pin circuit tester to see what that shows before I head to the dealer. Like a good lawyer, don't ask a question that you don't already know the answer to.....
Scargo did you purchase oem hitch “kit” 1663100195? What was all included in the kit you received? I found a website stating the following:
1663100118 qty 1 long member
1663100218 qty 1 long member
1663101137 qty 1 hitch
1663150065 qty 1 bumper foam
1664407013 qty 1 harness
1665404410 qty 1 harness
2469005501 qty 1 trailer controller
n000000003275 qty 8 nut
n000000003749 qty 2 screw
n000000006409 qty 4 bolt
n000000006964 qty 4 bolt
and seperately the def tank brkt 1664700181
Did you use all the parts in the kit? I have a 2013 BT and want to install the oem hitch but go aftermarket wiring. I cant find a picture anywhere of what the long members are and they arent in any parts list for my car. The bumper foam is only used on newer ml’s and gl’s from what i can see. Any help on whether or not you used these 3 parts would be very helpful.
theduge, yes, I used all the parts in the oem kit. The long members are heavy bars that bolt to hitch bumper and slide into the frame and bolts are installed in the spare tire area. You’ll see 4 holes, two on each side. It helps distribute weight closer to the rear tires so all weight is not on rear bumper. All of the parts you listed are included in kit, except ad blu bracket. You’ll have to trim the muffler shield but no big deal. if you don’t go factory wiring you’ll have all of the electrical parts leftover. The harnesses are set to plug in to the controller and fuse box under rear seat, and from controller to hitch plug.
Sorry it took so long to reply, I was on the road from Mexico. I don’t have any pictures but they’re about 24 in long, 3 in high and 3/4 in thick and the holes are threaded for bolts. There’s no real instructions in kit so it took me alittle time to figure out what they were for.
Went at it again with all good fuses in those slots, but still no reverse power at the hitch. I ordered a 7 pin circuit tester to see what that shows before I head to the dealer. Like a good lawyer, don't ask a question that you don't already know the answer to.....
Just as an FYI I have the factory hitch as ordered when the car came new.... I tow a 5000lb boat on 30 foot aluminum dual axle with brakes trailer..... that was a mouth full ? anyway the ml63 tows it with no drama... no sway at 65+....
Scargo- Do you remember what that blue empy connector was used for??
Originally Posted by Scargo
2012 ML 350 BluTec
I'm installing a factory hitch and need some assistance with the wiring harness.
There are two connections i need help with. On the brake control harness there are 2 connections, one is a small black/white wire with a pin connector and another small female two pin connector w/ brown and brown/red wires. was wondering if anyone knows where they connect or can send me wiring diagram.
Also on the controller,what wires connect to the blue connector?
Scargo- Do you remember what that blue empy connector was used for??
no, I don’t. The blue one is not used. I looked at the wiring diagram and it showed it tapped off the red plug. Maybe it’s for a different model like sprinter or R class
Hopefully you can help me. Looks like you are one of the few to have successfully installed the factory trailer harnesses.
I'm installing the same controller and harnesses in a 2015 ML350 (gas engine).
I don't need reverse lights or any of the electric brake controller functions (trailer and load weighs less than 1,000 lbs), just tail lights, turn and brake light, the usual flat, four-pin plug, stuff, so I am essentially just looking for the correct landing for 3 wires plus the ground.
I bought the 246-900-55-01 Tow Control Module, front harness 166-540-44-10 and rear harness 166-440-70-13. The module bolts to two obvious studs under the right rear panel and the rear harness goes just where you would expect it to.
I'm having trouble sorting out front harness wiring at the fuse panel. At the fuse block, I’m looking for the correct landing for the 5 load wires shown in the attached photo, plus the small black two-pin connector, which I suspect may provide an important function. Two of them I believe I know.
The front harness has two branches. One runs forward from the controller to the fuse block under the rear seat. There it splits off a second branch that runs forward to the underside of the dash for the brake controller, where it ends in a green 4 pin plug.
Playing with a circuit tester and turning lights, turn signals and emergency flashers on and off did not help. With the key on, the bus side of the block was constantly hot. That leads me to believe that these wires only supply power while perhaps the small black connector provides the operating signal to the controller? CANBUS or such?
The panel schedule calls out towing related fuses at the following locations:
20amp - F101 - From the length of the wires, this looks like this should be the red wire with the blue stripe.
5amp - F115 - The smallest fuse. This is the only location that has no fuse holder, and it is the only 5amp fuse. It has to be the supplied blue fuse holder, which came with a 5amp fuse.
30amp - F124 – The largest fuse. This is called out as power for the electric brake controller. The red wire with the blue stripe is heavier than the rest and it runs forward to the green 4-pin, so it has to be F124. I’ll install the wire, but leave out the fuse.
So, assuming F101 is right, that leaves me with two identical red wires with white stripes, 4 open fuse locations and the little black 2-pin plug.
Do you know of an easy way to route a new amp power cable from the rear to the battery without removing the rear seats?
Originally Posted by Scargo
Installed my facory OE hitch kit last weekend,labor intensive but got it done.
Took to dealership for recoding,no sam change required. It even added a
"SUV connected to a trailer" icon displayed when reverse camera is activated
and changes camera angle down for connecting to trailer tongue.
Total cost: 870.00 for hitch kit, 20.00 for adblue tank bracket, 236.00 for dealer recode, 1 1/2 hr labor.
Mike,
its been awhile science I did the install. Don’t remember exactly all connections,but I do know that the small 2 pin connects to the can bus at back corner of passenger seat under carpet and the n10 small single wire goes to front Sam in pass footwell behind plastic cover.
It all has to be connected and then the dealer has to reprogram brain for it to work. If I remember nothing works in 7 way trailer plug until trailer plug is connected.
The can bus connection is below the seat track by B pillar passenger side. N10 is Sam unit in passenger footwell right hand side behind cover. That wire connects to chamber 35. Photos might help. I used 2 wire t-stat wire to fish wire under carpet to front. It was just stiff enough and was still a *****
Last edited by Scargo; May 6, 2019 at 05:01 PM.
Reason: Add comments
For anyone that has had this done successfully, is there anything else that I need to do to select the "trailer icon" when the reverse camera is active? I had a dealership install the hitch kit and do the coding; the first time I picked the car up (2012 ML350 Bluetec) there was no "trailer icon" present on the comand screen. They assured me that everything was done correctly but they took a look through everything anyway when I brought the car back in and basically said again that everything was done correctly and if any feature was missing it was because I didn't have the "full tow package" (he was talking about more powerful radiator fans I believe and an oil cooler?). Lo and behold, when I went to leave the "trailer icon" was present this time but when I scroll over and try to select it, the icon flashes for a second but then reselects the normal "backing up" icon; none of the lines on the screen change during this. Is there something I'm missing to get it to work (have a ball in the reciever or anything?). They also said that fuses 101, 111, and 126 were not necessary for just the trailer hitch kit so anything they did was with those fusing missing. I put fuses in those spots, but that hasn't changed anything. Anyone have any ideas?
I don’t know how much you paid for the hitch kit and install, but the kit comes with all of those fuses and wiring for those slots. The full kit is about a $1000
and 2 dealers said they wouldn’t install it. Too labor intensive. See if you have trailer brake controller harness that runs up under dashboard driver side. No trailer has to be connected for icon to be active. My dealer didn’t have the proper software to update and had to have it downloaded from factory. Do trailer lights work when trailer is connected?
After I had the dealer program/enable the electronics, the trailer icon was present when reverse was engaged. I have tail lights, brake lights and turn signals. Never tried clicking or selecting the icon. What is that supposed to do?
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