Towing/Trailer Brake Relay

[deepseafortydog]

Greetings

I have a 2011 Treg V6 TDI. I was wondering if anyone has rigged their Treg for towing a trailer with brakes?

The trailer guy, who installed my trailer brake controller, said I would need an additional relay - from the dealer...

I'm not looking forward to a visit to the dealer for any reason, especially not for a $5.00 relay that they are going to ask $60 or so for.

Once I find out where the relay goes, and what type it is, I'm taking some pics and posting it here.

Thanks.

 

[redbarron55]

Do you have the factory trailer light package?
Not that this helps the brake question for electric trailer brakes.
I feel certain that you will need a brake controller like the Tekonsha P3 or other unit.
Most European trailers of the size of campers etc have surge brakes installed and no electric brake provisions.
The Touareg should have the proper modules installed or available for the trailer lights and to activate the Trailer ESP function as required in Europe.
I doubt your dealer has a clue, but you should ask them.

 

[deepseafortydog]

Thanks for the replies guys. I've been working through the info on clubtouareg. Still haven't found the unicorn.

So after adding some grease to the 7-pin connection, I headed over to see the dealer.. As we all thought, they don't know much more than I do about the Treg. They were, however, able to tell me that my rig was factory wired for towing by using the VIN.

I managed to get the trailer hooked up and all the lights work. The car did "recognize" that there was a trailer, as it disabled the rear hatch motor function. The controller I have is a Teconsha Prodigy 2.

Unless someone else has experienced the same issues and has a fix, I may have to take it to the dealer.. i.e. not the parts desk, but the service side.

 

[deepseafortydog]

Weeelll... The dealer had nothing. I feel like they are so incompetent.. They couldn't explain why I am not getting voltage to the controller power wire, nor any wiring or line diagrams to point me in the right direction.

 

[Tow-rig]

I bought a wireless Prodigy RF brake controller for my '11 Touareg. There is no need to hard wire it into the Touareg system, just plug the hand held control unit into a 12v outlet in the car and it communicates with the trailer mounted power module via bluetooth. I did need to add a LED lamp-out bypass adapter to the 7 -way flat pin that my trailer came with (Made by Tow Ready #20142, I think it was $20.00). Without this, the trailer brakes always locked up. With it, the car and trailer brake in coordination and the whole rig stops amazingly quickly (loaded, the trailer is about 4000 lbs).
If adding the by-pass adapter doesn't help, go to your nearest RV dealer and have them troubleshoot it for you. Your VW dealer will know nothing.

 

[andy7079]

It definitely sounds like a fuse or wiring problem. Can you test for 12V and ground continuity at the connector way up in the dashboard? You might consider a day pass on erWin to get the wiring diagrams.

 

[redbarron55]

What do you need the relay fro? The brake controller ( if it si something like the Tekonsha
P# requires a constant on power source preferrably direct from the battery protected by a 15 - 20 amp circuit breaker.
What is the relay for?
If used with the P3 it will lose its settings if the power is removed.

 

[andy7079]

What do you need the relay fro? The brake controller ( if it si something like the Tekonsha
P# requires a constant on power source preferrably direct from the battery protected by a 15 - 20 amp circuit breaker.
What is the relay for?
If used with the P3 it will lose its settings if the power is removed.

Certain model year Touaregs need a relay to switch the brake input to the controller. Something to do with there being a nonzero voltage on the brake input wire even when your foot is off the brake.

 

[redbarron55]

Have you tried the black with red brake wire tied to the brake controller?
On my JSW that black with red wire goes to the trailer module and I am going to use it to go to the brake controller also. I haven't yet hooked it up, but you may be looking fro an answer to a problem that does not exist.
The small voltage on the brake wire is for the computer to be able to detect an open or short on the line (I think).
When I installed the OEM trailer module in my JSW a part of the installation was tapping into the Canbus Hi and Lo and that black with red brake wire. When I did that I also tapped in a wire to go to my Tekonsha P3 brake controller.
Next up is to finish getting the power from the battery for the controller and a cutdown relay for the trailer power to kill the 12 volt to the trailer with the ignition off to keep from discharging the car battery.
I also need to do some work on the two wire trailer turn/brake system so that the brake/turn will work and also auto detect the trailer to turn on the T-ESP.
Do you know at what voltage your controller detects the brake signal?
There may not be a problem here at all.
If there is you could take a small 12 volt relay and have the brake signal pull it in.
I bet that this is needless complication, however I will soon be in the same position if I have a problem with my P3 in my 2013 JSW and I will come up with an answer then.

 

[redbarron55]

I have checked and the following is what I found on the E-Trailer site.
I don't know what controller you have, but I suggest the Tekonsha P3 to simplify things.

Here is what I found on the E-Trailer site.

Expert Reply:
I have confirmed with my contacts at Tekonsha, and Prodigy P2 # 90885 and P3 # 90195 have been re-engineered the to not require a relay for installing in a 2012 Volkswagen Touareg. The minimum voltage needed for the display on the brake controller has been increased, therefore the relay is not needed.

The 2005 to 2008 Volkswagen Touaregs and the Tekonsha brake controllers tech article was specific to those years of vehicles due to the Pulse Width Modulation signal supplied by the vehicle. If a relay was not installed then sometimes there would be erratic display on the brake controller. This was an interference signal that was sent through the stop light switch. Since the minimum voltage needed to activate the display on the P2 and P3 has been increased they have not experienced the erratic display issues like in the 2005-2008 models.

Since you have already established the wiring harness for under the dash the installation of the P2 brake controller will be straight forward.

You following wires on the brake controller will connect to the corresponding functions in your Touareg:
Brake Controller to Touareg Function
Blue - Brake wire to 7-way connection at rear of vehicle
Black - 12V power with an in-line circuit breaker
Red - stop light signal
White - Ground

 

[andy7079]

Good to know, so if I ever install a P2 on my Touareg it should be pretty straightforward.

 

[deepseafortydog]

Thanks for all the great replies! I never did get 12V power from the existing wire; and having to travel right away, I just wired a relay to a toggle switch, using a positive pin from the fuse panel that provides power when the ignition is in accessory mode.

I used a relay because I wanted a small switch to be able to turn the controller on when I was towing and off when I wasn't.

In any case, when I measured voltage from the existing brake controller harness, I didn't get more than .5V. Just didn't make sense. Anyone who finds out how to get power to those wires will have the ticket!

 

[redbarron55]

What brake controller did you buy?
If you had bought the P3 then there would be diagnostics and measurements of the brake system.
You may have a short in the brake circuit.
i am more than a little confused as to what you have wired in your system.
The P3 remains powered all of the time and uses little power unless it is being used (hooked to the trailer) The power keeps the settings alive.