[FinancialBull]

Hello all,
I purchased a 07' VW Touareg 6cyl used, which had a hitch and wiring harness installed. I'm pretty sure it was factory installed because I saw another post on these forums by a guy who also had the same set-up on his 06'.

Getting this ready for my 21' Mako, I looked high and low for an adapter that fit the strange looking receptor, but could not. So I decided to just snip it and wire up a universal 7-plug harness.

The problem, of course, is that I didn't take my time to find out what wire goes where (don't ask, lol). So now I have seven wires coming off my car (see first photo) which used to go in the Pollak adapter with the blue ring inside (second photo). I need to figure out which wire coming off my car goes where into the new adapter (third photo).

I have red, blue, black, yellow, green, a small brown wire and a large, thick brown wire. I don't know what does what, though I know the yellow is generally a turn signal, but the turn signal color code on my new adapter is blue, so...where does the blue one go (and so on and so forth through basically ALL the colors).

Does anyone know definitively which wire coming off the factory installed harness does what, OR any suggestion on how I could find out (would a voltmeter tell me what function each wire serves)?

Thanks y'all!
T

 

[Perry01]

You need the pollack connector available just about everywhere.

 

[FinancialBull]

Hi Perry, I may have not been very clear...I have a new 7-prong Pollak connector and 4-way boat trailer adapter which fit each other. I've cut out the factory Pollak weird plug (which has the blue ring in it in the photos) because I couldn't find anything that fit it. Now I'm stuck with 7 wires coming off my Treg, which aren't marked and are of all random colors, so I have no idea which wire does what. I'm trying to install the new 7-prong Pollak connector, but it's wiring diagram doesn't match up to the wires that are coming off the car.

So I'm looking for someone that knows what each wire coming off the T-reg does. Example:

Blue wiring coming off Treg... - brake controller
Green... - right turn
Yellow... - left turn
Black - 12v power
Brown - running lights/brake
Big brown - ground
Red - reverse lights

I'm just guessing with this diagram, I have no idea...I'm hoping someone does, though
Thanks!
T

 

[Lefty99]

Not sure if the volt metre will work as they don't present enough load for the Treg to pick up, but if you can rig something up with a tail light globe (20 watt) to hook up to the various wires and to ground then simply run through all the lights to see what comes on ( or flashes ). Iv done this plenty of times on other cars with good results ( might be a bit primitive but gives positive results )
Again I can't be positive, but the brown wire is the ground/negative wire on every other VW Iv owned. A way to confirm this would be with your meter testing continuity to a part off the body.
Also if you still have the pollock plug you cut off you might be able to cross reference the colours from that with a wiring diagram

 

[FinancialBull]

Again I can't be positive, but the brown wire is the ground/negative wire on every other VW Iv owned.

Which brown wire, the small or the big one? Did you have two different size brown wires? I used the colors on the back of the Pollak pigtail to try to match up wires, and I also believe the big brown wire is the ground (why the hell isn't it just white?!)

Thanks for the tips, Lefty. I think I can get this figured out...buying a tail light today!
T

 

[Niner]

Which brown wire, the small or the big one? Did you have two different size brown wires? I used the colors on the back of the Pollak pigtail to try to match up wires, and I also believe the big brown wire is the ground (why the hell isn't it just white?!)

Thanks for the tips, Lefty. I think I can get this figured out...buying a tail light today!
T

German... Ground = Earth.... Earth is dirt brown. So your ground wire is dirt or earth colored brown. Logical, in Continental Europe.

 

[Lefty99]

I believe there is a power supply for trailer ( battery charging ect. ) that is completely separate to the normal lights brakes circuits, so they have 2 ground wires, hence the 2 brown wires, but I can't say which one that would be

 

[ratbag]

Yes on that 7 pin connector in the pics above, the centre pin is the power supply for the trailer, and like you say it is completely separate to the brakes/lights etc. At least thats what is showed on the instructions that come with my new 7 pin connector assembly.

I trailer only boats so I never need power on the centre pin. Having said this, I'm sure power could be put thru any pin and work but as I recall the centre pin is a heavier duty round pin whereas the others are flat prongs.

I believe there is a power supply for trailer ( battery charging ect. ) that is completely separate to the normal lights brakes circuits, so they have 2 ground wires, hence the 2 brown wires, but I can't say which one that would be