Which is the cold Wire brake switch??? -Brake Controller NCV3 Video

Jpeixe sprinter

New member
We have a 2011 2500 Mercedes Sprinter and are trying to complete the Brake controller wiring. The red wire from the Brake Force brake controller needs to go to the cold wire coming from behind the brake pedal switch. There are 4 wires. The black/blue and the Blk/violet I understand are for the ESP system. The 2 Blk/Brown wires are looped together. Which one is the cold wire?
 

autostaretx

Erratic Member
Re: Which is the cold Wire out of the 4 brake pedal wires???

Well, i don't understand the meaning of the phrase "cold wire"... or at least it doesn't apply to the Sprinter.
(do you mean "the wire that would drive the brake lamps?)
Here's an extract from a 2007 wiring diagram, two of the wires go through a relay coil before getting to ground.

2007brakeswitch.gif

In the 2007, the Body Control Module module is what finally drives the brake lights themselves.
The Brake Switch talks to the Body Module via the Black/Violet wire that goes up in the first diagram.

2007BCU.gif

Added: found elsewhere in the print (repeats the first Stop Light Switch info, but it may feel a bit clearer)

2007stop3.gif

--dick
 
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showkey

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

My 2008 had the trailer brake harness in the battery box ready for connection to the trailer brake controller..................
 

sailquik

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

Hi Jpeixe sprinter,
Did your 2011 Sprinter come prewired from the factory with the towing package and
the receiver hitch?
If so, there is no need to do anything at the brake light switch.
All the brake controller and Trailer Control Package modules are under the drivers seat and
you can buy the correct green 4 pin male mating connector to wire in your brake controller from your Mercedes Sprinter dealer.
If your Sprinter did not come with the factory trailer wiring package, THEN you need to find the "signal" (not cold) wire in the connector at the back of the brake light switch.
Be careful at the switch operates backward from what you would consider normal.
Since the switch is past the fulcurm point for the brake pedal, when you press the pedal
down, the switch "opens" and you will find the signal wire easily with a meter.
Just make sure the wire you tap (use the adjacent jumpered port in the connector) is hot when you press the pedal and not when the pedal returns to the at rest position.
I know this as I was ready to tap into the wrong wire when I did my '06 Sprinter.
Pressed the pedal "one more time" just make sure and of course I had a wire that had current, but was not a signal wire the powered up when the pedal was pushed down.
Roger
 

Plouie

New member
Re: Which is the cold Wire out of the 4 brake pedal wires???

What wire is the cold wire on the brake light switch on a 2012 MB Sprinter without the factory trailer wiring?
 

Ben Bodie

Member
Re: Which is the cold Wire out of the 4 brake pedal wires???

I have a 2011 sprinter as well, that I'm hooking up a brake controller for.... I love how not a single person answered your question. Thanks guys.
 

autostaretx

Erratic Member
Re: Which is the cold Wire out of the 4 brake pedal wires???

I'd be happy to answer, but the term "cold wire" is simply too vague.

Does it mean "the terminal on the switch that is NOT already wired to a power source"? (that'd be my interpretation)

If so, it would be the black/violet (pin 4) wire at the switch in the last of the wiring diagrams i provided above
(and also goes directly to the tow connector, if you have that option).

It would become "hot" if the pedal was pressed. (and the key is on).

The original poster thought that color went to the EBS/ABS(etc)... but by the 3rd party diagram i have, the ABS is fed by the Black/Dark Blue wire.
BUT... that last drawing differs from the (same source, different page) first diagram i posted, which has Black/Red as the tied-together wires (on the "cold" side of the switch) ... and the original poster spoke of Black/Brown, which agrees with the last drawing.
That Black/Red drawing reverses the "hot/cold" sense of the wires/switch.

What colors are yours?

You could simply unplug the switch and turn on your key.
Now measure the voltages appearing on the connector that's attached to the Sprinter's wires.
From the drawing, two of them should be +12v "hot" (if the black/brown diagram is correct), relative to the battery's negative.

From the sounds of it, you're really looking for the wire that heads off to the brake light filaments.

--dick
 
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sailquik

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

Better question would be why is the OP looking at the brake light switch as a signal for installation of a electronic trailer brake controller.
That connection is supposed to be made under the drivers seat and he needs to add the trailer light/brake module and wire it correctly
to the Sprinters system.
Better still, order the retrofit trailer wiring kit and make the connections where the engineers @ Daimler Vans LLC specify in the kit
instructions.
Roger
 

showkey

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

I have a 2011 sprinter as well, that I'm hooking up a brake controller for.... I love how not a single person answered your question. Thanks guys.

The forum also “loves” when the OP never follows up in answering a few simple questions or explain the original question...............or better yet.......... post an explanation of the “fix” or what he found to help others reading this 6 years later.
 
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220629

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

I have a 2011 sprinter as well, that I'm hooking up a brake controller for.... I love how not a single person answered your question. Thanks guys.
The forum also “loves” when the OP never follows up in answering a few simple questions or explain the original question...............or better yet.......... post an explanation of the “fix” or what he found to help others reading this 6 years later.
I also love how some people expect answers because they are paying the members so much money for contributing.

Likely the OP isn't around here anymore.

Can anyone answer whether "cold wire" is the same as "switched wire". [Added: Answered. That is correct per the eTrailer video.]

Lots of people don't have the factory trailer wiring [with the included green plug]. When a signal is available (12 volts for older model controllers), it is common practice to get the trigger signal for the trailer brake controller by tapping the proper brake switch wiring.

At 17 minutes here "cold wire" is mentioned.

[Added:
Worthwhile for the INFORMATION that is shown about NCV3 Sprinters. Do watch the videos. Don't do everything that they do. Roger is correct that some of the techniques aren't the best. There are many other Sprinter related videos found on Youtube.]

https://www.youtube.com/watch?v=355649VGmus

It also mentions "pink with green" wire for the 2014. (As the trailer brake controller trigger.)

[Added after Dick's comment:
I didn't make the video. In the video he separates a wrapped set of 4 ea. wires. I can't tell what wire colors by the video. Maybe the guy is color blind? Regardless. It appears that the particular Sprinter in the video doesn't have the optional factory/OEM trailer harness with green connector. Even lacking any factory prep, the aftermarket brake controller is able to be connected to that 4 wire bundle for the necessary brake light trigger signal.]

The pink with green wire is not necessarily 12 volts. The newer models of trailer brake controller may respond to a trigger signal which is less than 12 volts.

Another related.
https://www.youtube.com/watch?v=3nbeHOlcF7I

An unrelated, but possibly useful video.
https://www.youtube.com/watch?v=b5raE1M20ZU

vic
 
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72chevy4x4

Well-known member
Re: Which is the cold Wire out of the 4 brake pedal wires???

the opposite of 'hot' wire in wiring would be a neutral wire, not cold wire.

I thought the OP meant ground wire, but that doesn't make sense why he would want a ground wire. Does the sprinter use a system where the ground is constantly supplied to a device and the positive is switched (CANbus)? If so, would the proper terminology be switched negative or switched ground?
 

autostaretx

Erratic Member
"Pink with green"???

Pink is not a color i've ever seen in any MB documentation.

(i'd look this up on WIS, but my access seems to have broken (the virtual PC can't reach the outside world for license verification))

--dick
 
An observation. A brake light switch is a normally open switch. Is is depicted as such in all drawings various posters have provided. As a normally open switch it has a "hot" side and a "cold" side when in the normal position. Therefore a "cold" wire with no electrical potential exists when the switch is in the normal position. The brake light circuit downstream of the switch is electrically "cold" until energized by the closing of the brake light switch.
The term "neutral" is better reserved for usage when referring to AC current.
Why did I respond? Because I do not want to use inline splices on the wrong wires, possibly damaging them in my attempt to install a brake controller on my '08 View on '07 chassis. Yes, I know how to probe the wires. But I came here for all the knowledge I could glean so as to minimize the results of mistaken assumptions.
It has been some time since I wired up a brake controller. And at that time there were just two wires to deal with. There was no Canbus to worry about.
Good luck to all!!!
 
Happy Thanksgiving to all.
Well, I have finished the brake controller installation in my 2008 Winnebago View 24H on 2007 Dodge Sprinter chassis. Let all the world know that for this model the violet stripe on black wire is the one to tap at the brake-light switch. My coach is a weird bird. It does not have the green connector under the driver's seat. It has a factory installed 5000# hitch with integral 6 round trailer port. Nowhere have I found mention of a 6 round port in Winnebago docs or by posters on various forums. Coincidentally, there is a female 6 round adapter plug in the black bag that was passed along with this coach. The 5000# hitch is contrary to docs that call out a 3500# hitch, but wears the 350# hitch weight sticker that Winnebago places. All wiring within the towing wiring harness are Winnebago yellows with white for ground. I ran into a serious problem with the E-brakes when I picked up a new trailer. Winnebago had wired pin (S) for stop-lights. Now, how often do you see separate stop-lights on a trailer? So there were no brake lights lighting up. Instead, the trailer tires skidded.
You can try every word combination to search for videos with explicit directions as to exactly which of the 4 wires to tap when adding a brake controller. There are none for the 2007 Sprinter.
Good luck to all!!!
 

autostaretx

Erratic Member
Is the "6 round" connector really what we're calling the "7 pin", since the central "locating pin" is also an electrical contact:

trailer.png

As the upper section of the 2007 drawing shows, MB brings the wires to a flat ten-pin connector, and then a "country specific" cable goes from there to the external connector.

--dick
2007 documents:
http://www.diysprinter.co.uk/reference/2007-sprinter-service-information.pdf <-2007 MB service manual
http://www.diysprinter.co.uk/reference/2007-sprinter-wiring-information.pdf <- MB wiring diagram from above
http://www.diysprinter.co.uk/reference/2007_Wiring-sprinter-2500.pdf <-- 3rd party wiring diagrams
 
6 round refers to a smaller connector having a total of 6 round pins. A 7 "flat" or "blade" connector has 6 flat blades with a central 2 bladed clasp for a total of 7.
Good luck to all and have a blessed Thanksgiving!!!
 

sailquik

Well-known member
Masked Man,
Do you have the OEM Build Data Card for your 2007 Dodge Sprinter Cab/Chassis that
Winnebago (your up fitter) converted into your 2008 Winnebago View 24H RV?
Often, I have seen that the up fitters (like Winnebago) do not order the "from the
factory" trailer towing crossmember and trailer towing electrical wiring harness.
The Mercedes Benz factory in Ludwigsfelde, Germany, (the MB Sprinter Cab/Chassis assembly
plant) does not install the trailer wiring or trailer tow cross member as they (Winnebago and
the other up fitters) do not include it in the massive fleet orders and choose to design/build/install their own trailer towing packages.
So, no factory green connector, no upper rail under the driver's seat with the trailer towing and
TSA modules because the up fitter did not order the cab/chassis with that option.
Start a conversation and send me your RV's VIN # and we can determine very quickly what was installed in Ludwigsfelde when your RV Cab/Chassis was assembled and tested.
Roger
 
Nothing from MB. Pasted inside of document bag that was passed along is a yellow/? card "Incomplete Vehicle Manufactured by DaimlerChrysler AG 07/07 Serial # 10537J259879 VIN WDXPF445X79348753 . The card has Manufactured by Winnebago Industries 10/07 in the upper left corner.
Thanks for your interest and help!!!
 

Diydisorder

New member
“Cold wire” is a common term used by brake controller manufacturers for the wire that is cold when not braking and hot when brakes are on.
 

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