Tow wiring loom

powbass

Member
Still looking or waiting to get my tow hitch wiring solved. Want the MB factory plug in system, not the plice in type. How the heck am I going to go fishing.
 

jmoller99

Own a DAD ODB2 Unit.
You may find that there are none left to order (depending on what year your Sprinter is). I had no issues splicing in a 4 wire controller and adding a 7 wire trailer/brake controller to that, I have towed a lot with it.
 

Iverj

Member
More info please...I just put a 2" hitch on my 2013 170 inch extended Sprinter. The harness for 2007 up came and it has instructions that are only pictures (no text). Unfortunately the pictures show the battery under the hood whereas mine has the battery under the drivers floor board.

What are the disasters in the making here?

Thanks,

Nelson
 

220629

Well-known member
... Unfortunately the pictures show the battery under the hood whereas mine has the battery under the drivers floor board.

What are the disasters in the making here?

Thanks,

Nelson
Do they mention connecting to the battery under the hood? The NCV3 OEM aux aka house battery is mounted under the hood. So it may be there in pictures, but isn't a factor.

Even if the 2007 harness will fit I would not buy it for a 2013.

The issue to me is that if your NAS aka NAFTA Sprinter is 2010 MY or newer the 2007 harness or aftermarket controller doesn't necessarily activate the Trailer Stability Program safety feature.

A properly installed aftermarket powered trailer light controller will still work on the newer Sprinters without problems.

If you only plan to tow a small trailer which doesn't have electric trailer brakes then I believe that having the trailer safety program is less of an issue. I say this because a major part of the Trailer Stability Program uses the electric trailer brakes for control.

:2cents: vic
 
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jmoller99

Own a DAD ODB2 Unit.
The trailer light controllers use solid state relays (ie. a mosfet that acts as one) - the current draw to cause the solid state relay to turn on is in the milli-amp range. This should not affect the Sprinter wiring - If you were simply to connect the light wires to the trailer plug, you will have problems. Using a $40 4 wire controller should not give you any problems.

I used a Tekonsha Prodigy T2 to drive the brakes (drive wire goes to one of the brake lights on the tail lights). With it, and towing a 5500 lb load (mid sized farn tractor and a lot of 12 foot horse gates and the rest of the trailer packed to capacity) - my Sprinter stopped like there was nothing being towed at all. The T2 only gives you braking control - you need the 4 wire controller to get the lights on the trailer working (I advise putting LED lights on the trailer everywhere possible to reduce its current draw).

Many of my tows have been in excess of 1000 miles each way (Moving a household and small farm from Illinois to Colorado). Often with 2000 lbs or more in the Sprinter at the same time.

If you can get the factory tow harness, get it. If not, you should still be able to get things working.
 

Iverj

Member
Howdy,

Vic and JMoller99, thanks for the response.

The harness was advertised by EuroCampers as "Sprinter OEM 7 Pin Factory Wiring Kit - 2007 - 2015 all models"

The plastic bag the harness is in is marked "MOPAR Original Parts and Accessories" and the harness itself has tags on it saying made in China (of course).

The instructions do not "mention" anything as it is entirely drawings (67 of them) showing how to hook it up and it does show it hooking to the battery.

I have not gotten around to trying to wire it up yet. I have the hitch on but I am in the process of wiring the van for 120 vac and 12 vdc for the various appliances etc.

I will use the hitch for a bicycle rack mostly, but also plan to build a trailer to carry my Harley Sidecar outfit. Total weight of bike and sidecar is probably around 1000 pounds plus the weight of the trailer which won't be much so I am probably not going to have anything other than surge brakes on the trailer.

I will try to remember to take pics and post how it goes if there are any problems or tricks others might need to know.

Thanks again,
Nelson
 

Trayscott

Member
OEM harness from Mopar just failed and blew the fuse and I am leaving tomorrow with a trailer. Put everything where they say. Relays in the sock thing totally exposed to water. All corroded. Installed last August! JUNK. Use a solid state controller from E Trailer. This is not rocket science as some claim. Trying to find OMRON replacement relays fast as I am leaving. 120 bucks out the window
 

powbass

Member
I had the M/B wiring loom installed by a well known sprinter mech. Took 3 trips . I have a 4 pole
conector on the hitch,, thats all I need no brakes on the trailer. When I plug into my trailer I get
a Brake warning on the dash. I have connected to other like trailers with the same results. I don't
think there will be any harm done, with just a brake warning. When I get the chance will make the
100+ mile trip back to the original installer,to see if there is a solution.This all took place on a 2014 cargo sprinter van.:cheers:
 

lindenengineering

Well-known member
For into that well known mechanics is my shop and staff !
Of course this apparent dissatisfaction is new to me until reading this post.

If you care to present the Van AND this time the trailer as a combination we might be able to config or pinpoint the problem.

In most of the case we find it is to do with the trailer lights, wiring ,bulbs (like LED's) etc since a test plug was installed into your trailer port socket at the point of installation and all the van circuits tested as good when the vehicle was in our shop in isolation.

Please call and make an appointment when you intend to come up as the shop is extremely busy every day, and of course we wish to make sure you leave with no warning lights on and with the trailer connected.

Cheers Dennis
 

Islander56

New member
Hi
I got the e trailer wireing kit for a 2014 sprinter watched the little video on their website installed it in about three hours.
Works great for three months now.
Islander :smilewink:
 

Trayscott

Member
Second set of relays corroded and burning up with dealer wiring harness. Gets wet in the quarter panel in the back. Was going to move it around, extend wires etc to get in in a dry spot and didn't. Plan z now. Only reason a light should come on is if the draw of the relays is such to make the system think there is a wrong size bulb. Dennis, I so rather pay you but you are too far away.
 

powbass

Member
Well I finally got the trailer wiring fixed. Had a dealer remedy the issue. After correcting a mis-conected wire at the module. The dealer sent an e-mail to the factory in Germany and recieved a code, which was programed into the vehicle. took aprox 5 hrs for the reply. Charged for 1 hour
($125) shop time. A dealer has it over independent garages as they have access to the factory .:cheers::cheers: PS: only cost over a grand to have trailer lights ::
 

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