Sprinter-Forum    
 

Go Back   Sprinter-Forum > NCV3 Sprinters > NCV3 Talk

NCV3 Talk General Discussions related to NCV3 Sprinters.


 
Thread Tools Display Modes
Old 02-20-2014, 09:26 PM   #1
aradsma
 
Join Date: Jul 2013
Posts: 29
Thanks: 0
Thanked 0 Times in 0 Posts
Default Trailer OEM Module Questions

Hello, I just got a 2007 Sprinter that appears to have the factory OEM module. I have tried to get it to work on a number of trailers, but every trailer gives me a different outcome. I have tried 3 different 7-way to 4-flat adapters on each, with the same results:

Trailer 1 (6x12 enclosed -regular bulbs): Brake works, left and right signals flash normal, but no running lights
Trailer 2 (5x10 open-regular bulbs): Brake works, left and right signals flash normal; no running lights, but right running lights flash same as the right turn signal
Trailers 3,4,5,6 (boat trailers, some with LED lights, most with regular bulbs): Didn't have someone to check brakes, left and right signals do a rapid flash (one super-quick flash every time the turn signal turns on), no running lights

I have measured with a voltmeter (with trailers connected) and never get any voltage out of the running lights pin.

Any suggestions what I can do to resolve this?

If your recommendation is to change the trailer module, can anyone confirm where it is located? I have seen some documents that say it is in the rear of the vehicle, and others that show it is under the drivers seat (see attached image - is that the location of the module?)

I also have a 20A fuse in position 14 (manual - "Trailer Socket") and a 25A fuse in position 15 (manual - "Trailer Recognition Device"). Do either of those mean I have Trailer Stability Assist?

I know some of these questions have been asked before, but I have never seen a resolution. Is there a troubleshooting guide for OEM trailer wiring?
Attached Images
File Type: jpg Trailer module location.jpg (119.4 KB, 195 views)
aradsma is offline   Reply With Quote
Old 02-20-2014, 09:42 PM   #2
mean_in_green
>1,800,000m in MB vans
 
mean_in_green's Avatar
 
Join Date: May 2007
Location: Hotel Mercedes
Posts: 2,885
Thanks: 31
Thanked 674 Times in 432 Posts
Default Re: Trailer OEM Module Questions

I had a fault with rapid indicator flashing when trailer connected. Proved to the dealer with a lightboard that it wasn't my trailer. It was the trailer module, replaced three times under warranty. The current one is about three years old now so whatever the issue was appears to have been resolved.

The dealer admitted they couldn't explain it further. As I didn't do it myself I can't help with the location except to say I believe it's under the seat.

Ask for warranty consideration as there clearly was an issue.

Last edited by mean_in_green; 02-20-2014 at 09:47 PM.
mean_in_green is offline   Reply With Quote
Old 02-21-2014, 03:19 AM   #3
aradsma
 
Join Date: Jul 2013
Posts: 29
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Trailer OEM Module Questions

Thanks mean_in_green.

Anybody else have funny operation out of the module? I found the part for $250 online - it would be nice to be a bit more sure that it is the module before spending the $$ on the part!
aradsma is offline   Reply With Quote
Old 02-21-2014, 04:06 AM   #4
sailquik
 
sailquik's Avatar
 
Join Date: Mar 2008
Location: Cape Hatteras, North Carolina
Posts: 8,870
Thanks: 3,135
Thanked 5,587 Times in 3,384 Posts
Default Re: Trailer OEM Module Questions

aradsma,
What makes you think you have the factory trailer towing package?
Is your receiver hitch cross member made by ORIS? Does it have a MB part number on it?
You do not have the OEM trailer assist feature....that wasn't added to NCV3's until 2010 or 2011.
Have you unplugged the connector on the back of the 7 way plug to test each wire coming from the
front of the van?
Having 3 different results from 3 different trailers sounds to me more like a trailer issue than a problem with
the Sprinter wiring.
Which pins in the 7 pin round connector in the back of the Sprinter give you voltage.
If I recall correctly the pin outs for the 7 way are molded into the cover for the female receptacle on
the back of the Sprinter.
You should be able to get Right turn....left turn and running lights + a ground out of your 4 way adapter.
Have you tried a different 4 way adapter?
There may be a "diode block" back in one of the rear quarter panels (this is sounding more like a T1N than
an NCV3) and diodes do go bad.
Follow the harness back from the plug on the rear of the 7 way and see if it goes into the body on the LH side.
If not, you probably have the NCV3 trailer wiring harness and the modules are up in the drivers seat box, but the
trailer module is usually the one up on the cross bar at the top of the box.
Hope this helps,
Roger
P.S. Send me a return email address and your VIN # by PM (up at the RH top of the page) and I can pull your data card
and confirm that your Sprinter had the factory installed towing package..
__________________
2014 Sprinter 516 series (3500 DRW) 170"/4325 mm wb Hi Top Short Back
OM-651 I4 2.143 liter two stage turbo charged with 36.9 PSIA MAP Limit Valve
7 Speed 7G-Tronic, manually shiftable, automatic transmission.
Suspension Seats, Active Safety Package +, Parktronic, OEM Hitch/wiring
OEM back up camera, Bi Xenon light package, fog lamps, headlight washers.
Had 2006 T1N 3500/158|2010 NCV3 519/3500/144|2011 & 2012 NCV3 519/3500 170

Last edited by sailquik; 02-21-2014 at 04:09 AM.
sailquik is offline   Reply With Quote
Old 02-21-2014, 01:26 PM   #5
aradsma
 
Join Date: Jul 2013
Posts: 29
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Trailer OEM Module Questions

Hello,

The hitch is the factory ORIS hitch, and has a bunch of german on the labels. I also have that module I circled underneath my seat, and the two fuses for the towing system, so I am quite sure that it is the 2007 NCV3 factory hitch setup I have.

I tried 3 different 7-round to 4-flat adapters, all with the same results. I also know that all these trailers work on 3 other vehicles, so I am quite certain that it is not the trailers.

If I measure the output on the 7-round connector with no trailer attached, I get 12V everywhere - I believe this is part of the trailer sensing circuitry. If I measure with a trailer attached (made an adapter that I can measure the voltage while a trailer is attached) I get normal type readings on the left/right turn signals, but it is really hard to tell with a volt meter since the lights are flashing... It reads 11V then low (~1V) and jumps around as they flash. There is no voltage on the running lights. The pin outs on the 7 way are molded into the cover - kind of handy for troubleshooting if you could only measure those with no trailer attached!
aradsma is offline   Reply With Quote
Old 02-21-2014, 02:45 PM   #6
sailquik
 
sailquik's Avatar
 
Join Date: Mar 2008
Location: Cape Hatteras, North Carolina
Posts: 8,870
Thanks: 3,135
Thanked 5,587 Times in 3,384 Posts
Default Re: Trailer OEM Module Questions

Adam,
Do you have the 4 little round parking sensors in the rear bumper of your Sprinter?
I think that is really what the "trailer sensing" module is all about.
If you put a trailer on the back of a Sprinter with the rear bumper sensors, the Sprinter's
systems have to be able to "sense" that it's there, which happens when you attach the trailer connector.
My guess would be that you might need to take your Sprinter to a dealer with the MB SDS diagnostic system and have
them check out the trailer sensing module.
Also sounds like you don't have a good ground pin in your 7 way. Might want to check the ground pin to the chassis of
your Sprinter. Should be 0.00 ohms (or very close to zero).
The fact that your turn signals go from 11 vdc to 1 vdc and back to 11 vdc indicates a possible grounding issue.
I just talked to someone very knowledgeable about this and it was suggested that the MB SDS can identify issues with these
modules.
Might cost for the diagnostics, but there may be no other way to ensure that the computers are playing nice with the trailer
wiring.
Just another thought, could you get a 7 way male connector and only hook up the wires you need, Brake lights/turn signals/running
and a good ground.
Also check the ground in your 4 way adapter (s) to the other 3 pins to ensure that it's completely isolated.
Hope this helps,
Roger
__________________
2014 Sprinter 516 series (3500 DRW) 170"/4325 mm wb Hi Top Short Back
OM-651 I4 2.143 liter two stage turbo charged with 36.9 PSIA MAP Limit Valve
7 Speed 7G-Tronic, manually shiftable, automatic transmission.
Suspension Seats, Active Safety Package +, Parktronic, OEM Hitch/wiring
OEM back up camera, Bi Xenon light package, fog lamps, headlight washers.
Had 2006 T1N 3500/158|2010 NCV3 519/3500/144|2011 & 2012 NCV3 519/3500 170
sailquik is offline   Reply With Quote
Old 02-22-2014, 02:10 PM   #7
aradsma
 
Join Date: Jul 2013
Posts: 29
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I don't have those sensors, so I don't think I have TSA, but somehow the electronics know when a trailer is attached. I have checked all grounds, and they are good. The changing voltages on the blinkers is normal too - it changes from 0v to 12v when it turns on the light for a second, the driver back to 0...my meter just can't keep up.

As for going to Mb, I get a sense that it would make more sense to just order the part. If it doesn't work, I can sell it again, but if it does, then I didn't pay Mb $250 to tell me I needed to buy a $250 part. I am scared of going in there and paying their service rates, especially if it is a phantom type problem that takes hours to diagnose.

Sent from my GT-I9100 using Tapatalk
aradsma is offline   Reply With Quote
Old 02-22-2014, 03:03 PM   #8
mean_in_green
>1,800,000m in MB vans
 
mean_in_green's Avatar
 
Join Date: May 2007
Location: Hotel Mercedes
Posts: 2,885
Thanks: 31
Thanked 674 Times in 432 Posts
Default Re: Trailer OEM Module Questions

I have Trailer Stability Assist. No rear parking sensors though, just the act of connecting the trailer plug enables the enhanced ESP.

Only felt it in action once, not going particularly fast but on trailing throttle downhill in a tightish bend. ABS pump had a mild workout.
mean_in_green is offline   Reply With Quote
Old 02-23-2014, 01:30 PM   #9
Motovan
 
Join Date: Feb 2014
Location: Burlington, Vermont USA
Posts: 9
Thanks: 3
Thanked 0 Times in 0 Posts
Default Re: Trailer OEM Module Questions

This happened to me too and it was perplexing to me and my dealer. I had a 5x7 haul mark with incandescent lights where the flashers and brakes worked but the running lights would only flash for a sec when hooked up. I fixed the issue by replacing some of my incandescent bulbs with led's. I think the output on the sprinter trailer harness is very weak. Try hooking up your trailer and unplugging one bulb at a time until the running lights pop on.
Motovan is offline   Reply With Quote
Old 02-23-2014, 05:31 PM   #10
Trayscott
 
Join Date: May 2013
Location: SOUTHEAST MICHIGAN
Posts: 504
Thanks: 123
Thanked 117 Times in 96 Posts
Default Re: Trailer OEM Module Questions

Roger, I need trailer wiring and preferably a Oris hitch. Your thoughts. Not ideal but a new sprinter is not happening. I understand the issue with aftermarket while keeping the step but is the aftermarket hitch mounted similarly to the factory hitch. Appreciate your input on the forum
Trayscott is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 06:14 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.