Trailer Wiring – DIY – without tapping wires! (55 pic’s)

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
I know a few people here have been waiting for this write up as I have been promising it and you’ll be glad to hear it works! I have successfully figured out a way to install trailer wiring WITHOUT cutting into or tapping the existing OEM wiring harnesses. I know there are faster and less expensive ways to install trailer wiring but I wasn’t comfortable using these methods. My desires were:

· not to tap, cut, or damage the existing wiring harnesses,
· to draw power from the battery and not off an existing circuit,
· to install a convertor that allows future power increases,
· to install wires for future uses such as a possible brake controller, auxiliary power, rear fog, backup camera, etc…
· to make a clean installation with the ability to remove the wiring if required in the future.

I did a similar system on my Passat but it was much easier as there were unused taillight connections and power from the battery wasn’t required.

This wiring design and installation took considerable planning. It is hard to tell how much time I spent on the entire installation as I dragged it out over a couple of months but I would say at the vehicle, it took about 6 to 8 hours. The hardest part by far was feeding the wires from the trunk to the engine compartment. I am fully aware a YouTube video shows it being run underneath the vehicle but that is the easy way out and leaves the wires susceptible to damage.

If you plan to use my ideas to attempt this on your own, I advise you get a Bentley Manual to understand how interior trim pieces are removed. You should also possess an understanding of basic VW wiring, housings, and terminals. There is plenty of information online about this if you need to brush up on your skills. I will not get into great detail of how interior pieces are removed or how terminals are removed from housings. I hope this gives you the confidence to try it and I’d be happy to assist you if you have any questions…send me a PM.


PARTS:
Modulite HeavyDuty Convertor 119190, HitchCity, $69.95
(2) VW REPAIR WIRES (male) 000 979 129A, Town+Country VW, $7.09ea.
(2) VW REPAIR WIRES (female) 000 979 133E, Town+Country VW, $6.60ea.
VW HOUSING (2 wire, male) 191 972 712, Town+Country VW, $8.89ea.
VW HOUSING (3 wire, male) 191 972 713, Town+Country VW, $8.39ea.
VW HOUSING (2 wire, female) 1J0 972 923, Town+Country VW, $3.39ea.
VW HOUSING (3 wire, female) 1J0 972 924, Town+Country VW, $6.60ea.
Inline Heavy Duty waterproof 15A mini-fuse and holder, Canadian Tire
(4) Heat Shrink Butt Connector for Multiple Wires (2 to 1), B&B Dixon Automotive, Pack $12.08
(2) Heat Shrink Butt Connector (10-12 AWG), Canadian Tire, Pack $5.99
(1) Heat Shrink Butt Connector (14-16 AWG), Canadian Tire, Pack $5.99
(2) Heat Shrink Ring Connector (10-12 AWG), B&B Dixon Automotive, Pack $12.08
10ga wire, black, (20 feet) - to battery, Princess Auto, 25’ roll, $12.99
OPTIONAL 12ga wire, blue, (20 feet) – future brake controller, Princess Auto, 25’ roll, $9.99
OPTIONAL 14ga wire, yellow, (20 feet) – future, Princess Auto, 25’ roll, $13.99
16ga wire (4 feet) - to ground

TOOLS:
VW Terminal Removal Tools, Schwaben from ECS Tuning
Wire Cutters/Strippers
Crimp tool
Lighter for Heat Shrinking
Torx Screwdrivers
Metric Socket set, 10mm, 13mm
Zip Ties
Silicone sealant
Electrical Tape
Coat Hanger/Fish

Other useful information:

Driver’s Side Wiring Harness:
Pin 1: Gray with Black Stripe: Tail Light
Pin 2: Black with Red Stripe: Brake
Pin 3: Brown: Ground
Pin 4: Black with White Stripe: Left Signal
Pin 5: Black with Blue Stripe: Reverse

Passenger Side Wiring Harness:
Pin 1: Gray with Black Stripe: Tail Light
Pin 2: Black with Purple Stripe: Brake
Pin 3: Brown: Ground
Pin 4: Black with Green Stripe: Right Signal
Pin 5: Black with Blue Stripe: Reverse

Here is the PLAN:

 
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vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
Now to find and gather all of the parts required:


25ft spools of 12V wire


Modulite HD Convertor with circuit protection, model #119190


HD Inline mini-fuse holder and fuses


Heat Shrink Butt Connector


Heat Shrink Butt Connector for Multiple Wires (Pack of 5)


Heat Shrink Butt Connector for Multiple Wires


Heat Shrink Ring Connector (Pack of 5)


Heat Shrink Ring Connector


VW Repair Wires (female) 000 979 133E


VW Repair Wires 000 979 133E, close up
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen

VW Repair Wires (male) 000 979 129A


VW Repair Wires 000 979 129A, close up


VW Housing (3 wire, male) 191 972 713 and
VW Housing (3 wire, female) 1J0 972 924


VW Housing (2 wire, male) 191 972 712 and
VW Housing (2 wire, female) 1J0 972 923
The only reason I went with a 2-wire over a 1-wire is that this housing is half the cost!


VW Terminal Removal Tool by Schwaben, this was a great purchase!


Schwaben Kit from ECS Tuning (open)


Schwaben Kit (closed)


First step is to cut the four Repair Wires in half.


This will give you four male leads and four female leads.
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen

Insert three male leads into the housing ensuring they snap in place. The snap the redundant safety on the housing to lock them in.


Strip about 10mm off the end of each Repair Wire.


I labeled the wires to keep it clear.


Next, I used the 2-to-1 Butt Connectors to start making the harness.


Using the crimping tool crimp the connector.


This is what it should look like.


Then using a lighter, melt the connector to form a waterproof seal around the wires.


Convertor harness is completed.


Another view of the heat shrink butt connectors.
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
Now time to start taking the car apart.


Remove the rear sill, 2 plastic caps to come off….


Then it simply pulls straight up…here is the left side…



Here is the right…


Next in the back seat, you’ll need to remove the side air bag (of course you have disconnected the negative terminal on the battery first!).


Here is the bolster removed…some strange connectors to hold it in place.


Here is the bottom of the bolster…this metal “U” slides behind a clip to hold it tightly in place.


I did remove the whole trunk trim which took about 3 to 4 hours but was worth it in the end. (Sorry no pics here)….It was worth it as it exposes Ground Point 662 which is a factory ground point and also allowed free access to the place I planned to run the wires.


Here is the wiring harness of three wires that I wanted to run from the back of the car to the front…(1) 10ga (black), (1) 12ga blue), and (1) 14ga (yellow). I taped then together so they could be pulled together.


Close up.
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen

Starting in the trunk…


I didn’t document the whole journey of the wires but in essence they run behind the left trunk panels and down behind the rear driver’s side rear seat air bag. I wrapped the wires in felt to ensure they wouldn’t rub up against any sharp surfaces and also wouldn’t vibrate. From the back seat, I was able to tuck them under the plastic sill, under the driver’s seat belt, and then I needed to pull up the driver’s sill. I was then able to get them directly under the sill behind the clips and then up under the hood release above the dead pedal… For the life of me I cannot figure out how to take the hood handle off as Bentley isn’t that clear but I was able to get it there without taking it off. I removed the panel above the foot well simply by removing the two T20 screws, and removed the light connector and the diagnostics port.


Now under the hood…remove the battery terminals and then the battery. You’ll need a 13mm socket to loosen the metal clamp that holds the battery in place…be careful not to drop the bolt down into the lower engine….if you do a magnetic removal tool may come in handy…


Looking back to the firewall about and around the main harness you’ll see a series of small nipples than are meant for wires…in this pic there are four visible…


From the inside I opened up a coat hanger and found the inside of the nipple on top of the large wrapped VW wiring harness and pushed it through…


Back under the hood, the hanger was there…


Back into the foot well I attached the hanger wire to the 10ga wire…


Then wrapped with electrical tape to make sure nothing comes undone or catches on the rubber boot…


I then went back under the hood and pulled the wire through….notice how well it self sealed itself…I still added some silicone to it just to be safe. I zip tied the wire to a part of the frame such that it wouldn’t be just hanging loose.


I put the battery back in and put the insulating sleeve around it…next was to attach the inline fuse to a Heat Shrink Butt Connector and a Heat Shrink Ring Connector..
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen

Crimp the connection and melt with the lighter.


Don’t forget to install the 15A fuse (I did this at the very end.)


Here is the driver’s side tail light as per the diagram in Post #1


Here is the passenger side….


I mounted the convertor to the inside of the spare tire well.


I then cleaned up the wires by zip tying them in place…


For the final step, I pulled the four-flat plug through the grommet, sealed the opening with silicone, and attached it to the Westfalia pull down mount.

I put in the 15A fuse, drove the car down to my trailer, attached it, did a full test and it worked flawlessly….woohoo!!!
 

Arne in Oregon

Veteran Member
Joined
Jun 28, 2010
Location
Oregon
TDI
'10 Golf MT6
Many thanks for including the part numbers. While I may not do it identically to yours, those numbers will allow me to do something very similar for my Golf. Two big thumbs up!
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
Thanks Arne...I think the write up took as long as the install! LOL

If anyone needs the wiring diagram, I have a PDF at higher resolution that what is shown here and I could email it....send me a PM if you want it with your email address.
 

cevans

TDIClub Enthusiast, TDI Parts Ninja Vendor , w/Bus
Joined
Sep 24, 2002
Location
Hingham, MA
TDI
2015 Beetle Conv. TDI 6-Speed & 2006 E320 CDI
I've been working on a complete plug-in system, no extra wiring, by using the female version of the OEM taillight connector. Plug the OEM harness into the trailer harness, plug the trailer harness into the back of the housing, viola. I'm planning on matching this with a 12V plug to get full power, the idea being a 1 min install or removal.

For reference -
5 Pin Connector : 6N0 972 705
5 Pin Female Housing : 191 972 715
 

Arne in Oregon

Veteran Member
Joined
Jun 28, 2010
Location
Oregon
TDI
'10 Golf MT6
I've been working on a complete plug-in system, no extra wiring, by using the female version of the OEM taillight connector. Plug the OEM harness into the trailer harness, plug the trailer harness into the back of the housing, viola. I'm planning on matching this with a 12V plug to get full power, the idea being a 1 min install or removal.

For reference -
5 Pin Connector : 6N0 972 705
5 Pin Female Housing : 191 972 715
This was my plan initially, but I'm thinking that doing it the way Leadfoot did will be simpler, albeit a bit more time-consuming to reverse later. But thanks for the part numbers, they will be great to have should any of us wish to do it this way.
 
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TurboHokie

Member
Joined
May 6, 2007
Location
Fayetteville, GA
TDI
02 Jetta GLS, 14 Sportwagen
Hood Release removal

I was then able to get them directly under the sill behind the clips and then up under the hood release above the dead pedal… For the life of me I cannot figure out how to take the hood handle off as Bentley isn’t that clear but I was able to get it there without taking it off.
VW_leadfoot, great write up and VERY HELPFUL when I did my own install over the weekend. It's about time I contribute though--I figured out how to remove the hood release, you need to pull it to the open position, which exposes the side that faces the front of the car. You can do gymnastics under the dash and see a slot on the handle where the retaining clip goes, or just feel for it (sts). Take a big flat screwdriver or trim tool and pry out the clip. Then, covered by the handle, there is a small 1/4" size plastic trim button - pry that off to expose a plastic trim screw. Unscrew and the panel should come right out.
 

Mainely Diesel

Active member
Joined
Sep 14, 2011
Location
Maine, USA
TDI
2011 Jetta Sportwagen
Amazing photos and details, I really appreciate what you have done and will be doing exactly the same thing to mine soon.

Just to clarify: the yellow and blue wires that you ran to the front with the black lead were not connected to anything at this point, right? You simply ran them so that you could use them for some undetermined future need, right? Just want to be absolutely sure because it appears that they were left unconnected under the dash rather than being run into the engine bay. You mention a variety of possible uses for the extras but do you have any specific thoughts beyond a brake controller for uses?

Thanks again for the step-by-step, it is really super-helpful.
 
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notyetanewbie

Well-known member
Joined
Feb 26, 2002
Location
Ohio
TDI
2011 JSW (white, DSG)
Nice detail!

When I installed a Tekonsha brake controller on my van it called for an auto reset circuit breaker for the electric brake power line. I think their manuals are online.

I have not looked into wiring for trailer lights for my JSW, but is it possible to buy pre-fabricated harnesses that plug into the existing tail light connectors? I think I used one made by Draw-Tite. Pretty simple install, at least for the lighting.
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
Amazing photos and details, I really appreciate what you have done and will be doing exactly the same thing to mine soon.
Just to clarify: the yellow and blue wires that you ran to the front with the black lead were not connected to anything at this point, right? You simply ran them so that you could use them for some undetermined future need, right? Just want to be absolutely sure because it appears that they were left unconnected under the dash rather than being run into the engine bay. You mention a variety of possible uses for the extras but do you have any specific thoughts beyond a brake controller for uses?
Thanks again for the step-by-step, it is really super-helpful.
Thanks :)
That is correct. The blue and yellow wires aren't connected to anything yet. They are not into the engine bay and remain tucked up above the plastic panel by my feet. I may use the yellow for my future rear fog and the likelyhood of needing a brake controller isn't going to be a reality anytime soon.
Nice detail!
When I installed a Tekonsha brake controller on my van it called for an auto reset circuit breaker for the electric brake power line. I think their manuals are online.
I have not looked into wiring for trailer lights for my JSW, but is it possible to buy pre-fabricated harnesses that plug into the existing tail light connectors? I think I used one made by Draw-Tite. Pretty simple install, at least for the lighting.
There aren't any open plugs in the tailights of a JSW so it would need to be hardwired somehow...
 

P0234

Veteran Member
Joined
May 18, 2011
Location
NoVA
TDI
11 JSW
Awesome thread, documenting this well takes lots of time and hard work, thanks OP!
 

jdbski

Member
Joined
Oct 12, 2008
Location
new jersey
TDI
2012 sportwagen
I've been working on a complete plug-in system, no extra wiring, by using the female version of the OEM taillight connector. Plug the OEM harness into the trailer harness, plug the trailer harness into the back of the housing, viola. I'm planning on matching this with a 12V plug to get full power, the idea being a 1 min install or removal.

For reference -
5 Pin Connector : 6N0 972 705
5 Pin Female Housing : 191 972 715
did you ever complete this system and if so can i buy it?
 

Bighook

Member
Joined
Mar 4, 2011
Location
Calgary Alberta,Canada
TDI
2011 Golf TDI
Wiring a 2011 Golf

Hey Leadfoot, fantastic wiring job,lots of details. I'm currently in the process of adding a brake light modulator to my 2011 Golf tdi, which has only the 3 pin connectors on the taillight/turn signal assembly.I was curious as to what the 2 wire connectors were for , as well as why you purchased only 2 of eack repair wire when it calls for 3.If you could shed some light on this I would be most appreciative. as well as the wiring diagram! cheers
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
....I was curious as to what the 2 wire connectors were for , as well as why you purchased only 2 of eack repair wire when it calls for 3.....
Two wire connectors were used for future easy removal of the system. In the write up I stated that I used a two and a three wire housing to join the wires and allow for easy removal. The two could have been a one but they were more expensive.

Repair wires are cut in half and thus if you have one wire you actually have two terminals. Cutting it in half gives you double the quantity of terminals.
 

MF1160

Active member
Joined
Jun 24, 2011
Location
Southeast
TDI
2015 BMW X5 35d xline
Leadfoot
THANKS for the writeup
Worked perfect on my 2011 Jetta, trailer now has lights, YAHOO!
The pin pusher kit was a bit steep in price, cant imagine trying to remove the wires without it however.

Thanks,
Tom
 

vw_leadfoot

Veteran Member
Joined
Apr 8, 2010
Location
GTA, Ontario
TDI
2010 Golf TDI Wagen
Leadfoot
THANKS for the writeup
Worked perfect on my 2011 Jetta, trailer now has lights, YAHOO!
The pin pusher kit was a bit steep in price, cant imagine trying to remove the wires without it however.

Thanks,
Tom
That's excellent Tom. Glad it worked out!


Sent from my iPhone using Tapatalk
 

jdbski

Member
Joined
Oct 12, 2008
Location
new jersey
TDI
2012 sportwagen
using existing 12v outlet in trunk for power

That's excellent Tom. Glad it worked out!
Sent from my iPhone using Tapatalk
can you give me any advice if i wanted to use the existing accessory outlet in the trunk area to power the tailer wiring module?
thanks,
jb
 

Nizle

Active member
Joined
Dec 3, 2011
Location
Carlsbad
TDI
2012 Golf TDI
Has anyone found part numbers for a female/male connector that will plug into the mk6 2012 golf yet?
 

Jedadiah

Veteran Member
Joined
Sep 17, 2010
Location
Central Kentucky
TDI
Former: '15 Passat TDI SE 6M, '15 Golf S 6M and '10 JSW
Female and Male Connectors

Aside from my 2010 Wagon, I also have a 2007 Rabbit and I used the follwing VW parts to add a section to the harness that I could then splice into and not in to the factory wiring. I plug the factory harness into one side and the tailight into the other. I don't know if it's the same on a 2012 Golf, but it could be. These are 4 Pin connectors, but my lights only used three of the pins

Female connector: Ik0 972 774
Male connector: Ik0 972 764

The female repair wire for this connector is 000 979 151 EA
The male repair wire is 000 979 134 EA

The connectors are fairly cheap. The repair wires are kinda pricey. It cost me $70 to make the connectors ording from 1st VW Parts. The nice part was that I didn't have to remove any factory wires from thier terminals and could simply unplug the trailer wiring and remove it if I decided to sell the car.
 
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Jedadiah

Veteran Member
Joined
Sep 17, 2010
Location
Central Kentucky
TDI
Former: '15 Passat TDI SE 6M, '15 Golf S 6M and '10 JSW
Connectors

Here is a picture of the tailight connector and of the passenger side wiring section I made. If your tailight plug looks like the one pictured than the parts numbers should work for you. The other part number fits this plug. I'm not sure what it was origionally from. 1st VW Parts used their ETKA to find the part number.


 
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SA_TDI

Well-known member
Joined
May 6, 2003
Location
Cle Hts, OH
TDI
2005 PD GLS- BEW
Thanks for the exceptional and well documented post. I am not looking to go into as much detail but rumor has it that there "could" be a kit out there that allows an install where no splices need to be made. Is this possible?


I've been working on a complete plug-in system, no extra wiring, by using the female version of the OEM taillight connector. Plug the OEM harness into the trailer harness, plug the trailer harness into the back of the housing, viola. I'm planning on matching this with a 12V plug to get full power, the idea being a 1 min install or removal.

For reference -
5 Pin Connector : 6N0 972 705
5 Pin Female Housing : 191 972 715
 

30Bones

Veteran Member
Joined
Jun 27, 2006
Location
Cedar Rapids, Ia
TDI
2013 Touareg TDI
Thanks for the exceptional and well documented post. I am not looking to go into as much detail but rumor has it that there "could" be a kit out there that allows an install where no splices need to be made. Is this possible?
I am all ears. I enjoy wiring, but am the first to admit my work is less than photo worthy.
 
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