Wiring Electric brake controller into VW T5

[lemmiwinks]

I've just purchased a Tekonsha P3 Electric brake controller, supposedly top of the line stuff. As I'm planning to do some 2.5T towing.

Where is the best place to connect the brake light signal? I've currently got a genuine VW tow bar wiring kit and hitch. Did a quick search and haven't really found any useful info..

[Hillbilly]

I've just purchased a Tekonsha P3 Electric brake controller, supposedly top of the line stuff. As I'm planning to do some 2.5T towing.

Where is the best place to connect the brake light signal? I've currently got a genuine VW tow bar wiring kit and hitch. Did a quick search and haven't really found any useful info..

Dont know about the VW but I have always connected it to the cold side of the switch on the brake pedal

They are an excellent controller when set up correctly Have towed vans for 50,000km over 2 years using the Prodigy model

Black goes to battery white is earth red to cold side of switch Blue to pin 5 of a normal 7 or 12 pin connector

[Skoda VW]

Have been through this headache myself twice. Once on my Skoda and the second time on my T5 Facelift. Here is what I posted on an amarok forum back in 2011. Not sure if it is the same on the earlier T5.

I recently installed an Electric Brake Controller in my 2011 Multivan. Like you it was all to hard for anyone to work out. Ended up installing myself. I TAKE NO RESPONSIBILITY FOR ANY DAMAGE IF YOU FOLLOW MY ADVICE. I am not an auto electrician.

The Problems -

1. VW use CANBUS system and there is no "Brake Switch" as such. It is part of the brake master cylinder assembly.

2. The 13 pin Euro to 7 Pin Flat adaptor supplied by VW is annoyingly short. Also if you buzz out the connector the brake pin in the flat connects to pin 2 in the euro which is "rear fog light"....WTF. When they made the adaptor they went colour for colour and blue in the Euro standard is for fog light.

I thought about taking the 13 pin off and installing a standard 7 pin round, but there is a switch built into the 13 pin euro socket and due to the CANBUS and not knowing exactly how the electronics in the vehicle react to the switch state I decided to leave it installed.

Solution -

I made my own adaptors and cut the cables off my caravan and trailer. I installed 7 pin round sockets on both the caravan and trailer which allows me to easily change towing cars. Same as what trailer hire companies have done to their rigs.

I purchased the Euro connectors off Ebay (I had trouble finding anyone who stocked them in Oz). Pin 12 in the euro connector standard is listed as "Coupled Trailer" or "Not assigned" depending on which website you use. I used this pin for electric brake as there is no assignment in the spec for Electric Brakes. They don't use them in Europe.

There is a trailer control box mounted in the Multivan under the front passenger seat. I did all wiring on the Euro socket side of control box to keep the brake controller completely isolated from the CANBUS.

In the wiring loom there is also a 2 pin connector floating about with nothing connected to it. One wire Yellow and the other White/Brown. These two wires go directly to pin 10 and 11 in the euro socket. Pin 10 "Switched 12V" and pin 11 "Earth return for pin 10". I took the wire out of pin 11 on the socket and put it into pin 12. I used this wire for the brake control output to the rear. Use the other wire to connect to a relay for switched 12V for your fridge. Only perm 12V on pin 9 is availble in the socket. REMEMBER wire your adaptor for these changes.

I tapped off the stop signal on the output of the trailer contol box and used it as the brake input to the electric brake controller. THERE ARE THREE PROBLEMS USING THIS AS YOUR BRAKE SWITCH SIGNAL.

1. If you have cruise control on and you apply brake to the trailer using the switch on your controller the cruise control will not auto disengage. I figure if your trying to stop sway in your rig you don't want to back off on the accelerator when applying trailer brake anyway.

2. When you apply brake to the trailer using the manual overide, the brake lights on your car won't come on only the ones on your trailer. If I'm towing my caravan you can't see my car brake lights if your behind me anyway.

3. When you apply trailer brake manually I think it gives a faulty lamp indication on the dash. It goes out when you restart the car. May be able to get rid of if you fit a isolation diode in line. Think I did this on my Skoda but can't remember. I would need to have another look.

Wire up 12V and Earth as normal to your controller and your done.

I have wired my 2008 Skoda Scout a few years ago and have towed many km's without issue. The only difference is that they perm mount the adaptor on the car and I did all the wiring in the flat 7 pin connector at the back and not directly at the control box.

I hope I have helped in some way as when I did my Skoda I couldn't get any info and searched many forums on VW electric brake installs. Apart from the Touareg forums there isn't much info. The Touareg seems to be wired differently to other VW models for the US market.

When you are paying $1600 for a dealer fitted towbar it is pretty poor that VW haven't thought about the issue of installing electric brake controllers into their vehicles.

[Sunny43.5]

I am also not an auto elec but I recently wired up our trailer on our new T5 and went through the problem of a ridiculous price for factory loom , simple solution for me was a Hayman Reese unit , and this is how I figured out how to defeat VW's system if you just connect a wire to the brake light signal at the taillight, the system will read the extra load and have a heart attack .Solution which is what I had already thought about until I bought the Hayman Reese is you tap into the brake light wirew at the tail light but run that signal into a relay when wired up corrctly the car system cannot read a signal load as its not drawing power via the relay . It might be one way to do the job would also suggest that you could also use a diode protected relay for more piece of mind .

[Transporter]

Just a word of caution.
A customer of mine (that I know for 22 years) asked me to install the brake controller in his Touareg. I politely declined with recommendation to use the electrician who does it every day and more importantly who done the Touareg before and is familiar with VW electrics.
However, the electrician made a mistake and connected something to the brake light that he shouldn't have, car refused to start, it took them an hour or so to get it started but there is a fault now with the oil pressure gauge circuit and annoying ding with the fault message every minute or so, as a result of the damage to the body control module.

[Hillbilly]

Have been through this headache myself twice. Once on my Skoda and the second time on my T5 Facelift. Here is what I posted on an amarok forum back in 2011. Not sure if it is the same on the earlier T5.

I recently installed an Electric Brake Controller in my 2011 Multivan. Like you it was all to hard for anyone to work out. Ended up installing myself. I TAKE NO RESPONSIBILITY FOR ANY DAMAGE IF YOU FOLLOW MY ADVICE. I am not an auto electrician.

The Problems -

1. VW use CANBUS system and there is no "Brake Switch" as such. It is part of the brake master cylinder assembly.

2. The 13 pin Euro to 7 Pin Flat adaptor supplied by VW is annoyingly short. Also if you buzz out the connector the brake pin in the flat connects to pin 2 in the euro which is "rear fog light"....WTF. When they made the adaptor they went colour for colour and blue in the Euro standard is for fog light.

I thought about taking the 13 pin off and installing a standard 7 pin round, but there is a switch built into the 13 pin euro socket and due to the CANBUS and not knowing exactly how the electronics in the vehicle react to the switch state I decided to leave it installed.

Solution -

I made my own adaptors and cut the cables off my caravan and trailer. I installed 7 pin round sockets on both the caravan and trailer which allows me to easily change towing cars. Same as what trailer hire companies have done to their rigs.

I purchased the Euro connectors off Ebay (I had trouble finding anyone who stocked them in Oz). Pin 12 in the euro connector standard is listed as "Coupled Trailer" or "Not assigned" depending on which website you use. I used this pin for electric brake as there is no assignment in the spec for Electric Brakes. They don't use them in Europe.

There is a trailer control box mounted in the Multivan under the front passenger seat. I did all wiring on the Euro socket side of control box to keep the brake controller completely isolated from the CANBUS.

In the wiring loom there is also a 2 pin connector floating about with nothing connected to it. One wire Yellow and the other White/Brown. These two wires go directly to pin 10 and 11 in the euro socket. Pin 10 "Switched 12V" and pin 11 "Earth return for pin 10". I took the wire out of pin 11 on the socket and put it into pin 12. I used this wire for the brake control output to the rear. Use the other wire to connect to a relay for switched 12V for your fridge. Only perm 12V on pin 9 is availble in the socket. REMEMBER wire your adaptor for these changes.

I tapped off the stop signal on the output of the trailer contol box and used it as the brake input to the electric brake controller. THERE ARE THREE PROBLEMS USING THIS AS YOUR BRAKE SWITCH SIGNAL.

1. If you have cruise control on and you apply brake to the trailer using the switch on your controller the cruise control will not auto disengage. I figure if your trying to stop sway in your rig you don't want to back off on the accelerator when applying trailer brake anyway.

2. When you apply brake to the trailer using the manual overide, the brake lights on your car won't come on only the ones on your trailer. If I'm towing my caravan you can't see my car brake lights if your behind me anyway.

3. When you apply trailer brake manually I think it gives a faulty lamp indication on the dash. It goes out when you restart the car. May be able to get rid of if you fit a isolation diode in line. Think I did this on my Skoda but can't remember. I would need to have another look.

Wire up 12V and Earth as normal to your controller and your done.

I have wired my 2008 Skoda Scout a few years ago and have towed many km's without issue. The only difference is that they perm mount the adaptor on the car and I did all the wiring in the flat 7 pin connector at the back and not directly at the control box.

I hope I have helped in some way as when I did my Skoda I couldn't get any info and searched many forums on VW electric brake installs. Apart from the Touareg forums there isn't much info. The Touareg seems to be wired differently to other VW models for the US market.

When you are paying $1600 for a dealer fitted towbar it is pretty poor that VW haven't thought about the issue of installing electric brake controllers into their vehicles.

Alll very good advice as it seems to be a bit of a nightmare.

One small thing to be considered is that it would be best if you could get the brake wire in the adapter to be on pin 5 at the van.
Reason being is should another vehicle get to tow the van for whatever reason there will be no brakes working on it.
It may not happen very often, if at all but may cause anguish should anything go wrong when the van has no brakes.

Have seen lots of trailers with non standard wiring that blow fuses and have brake lights permanently on due to not observing wiring protocols

[Umai Naa!!]

There's a pin-out under the passenger's seat that you can untilise for a brake light signal. Applicable to both the T5 and T5GP (Facelift).

Failing that, I'm pretty certain you can use the output from the brake light switch on the T5, but on the T5GP, you need to use the output from the hall sensor on the brake master cylinder.

[lemmiwinks]

There's a pin-out under the passenger's seat that you can untilise for a brake light signal. Applicable to both the T5 and T5GP (Facelift).

Failing that, I'm pretty certain you can use the output from the brake light switch on the T5, but on the T5GP, you need to use the output from the hall sensor on the brake master cylinder.

What colour wire is this wire under the passenger seat for the brake signal. I've just purchased everything i need for the install and will be doing it tomorrow.