Tow Bar control of Braking etc

[MurrayR]

Last year I had a Tow bar fitted by my local VW agent. When I used it for the first time recently I noted that the alarm sounded from the rear sensors as they picked up the trailer. What do I need to purchase to check that the Van has been set up correctly as most posts report that the rear sensors should not sound with a trailer properly connected? At the time of installation I know they had issues with the programming.

Many thanks,
Murray
VW Cali 2007

 

[WelshGas]

Last year I had a Tow bar fitted by my local VW agent. When I used it for the first time recently I noted that the alarm sounded from the rear sensors as they picked up the trailer. What do I need to purchase to check that the Van has been set up correctly as most posts report that the rear sensors should not sound with a trailer properly connected? At the time of installation I know they had issues with the programming.

Many thanks,
Murray
VW Cali 2007

I presume it was the Proper VW wiring kit that stretches from the rear all the way to the front of the vehicle and then programmed into the vehicle electronics?

If so, then it has been incorrectly programmed.

If it was a generic Towbar wiring kit, tapped into the rear wiring then you have a problem.

 

[DM]

I believe that the vehicle knows about the existance of a trailer via a valid electrical connection. So if you haven't plugged in then the sensors will pick-up the trailer.

It also disables side assist. Presumably because side assist only protects the portion of the road needed for the van - not van plus trailer. Frustrating though as I'm generally only using a bike rack which only extends the length of the vehicle by about a metre.

 

[jts46]

As it is a 2007 model, just switch off sensors as i do when i have a trailer connected using switch on dash board?

 

[MurrayR]

This was fitted with a VW part and I paid much more than a standard tow bar cost. I am more worried about the effect on the braking if towing a Caravan.

 

[DM]

This was fitted with a VW part and I paid much more than a standard tow bar cost. I am more worried about the effect on the braking if towing a Caravan.

Not sure that there is any risk to braking here. I'm pretty sure that the interaction between the van and trailer for disabling sensors is electrical - not mechanical. So the only risk is that the brake lights on the trailer may not work.

But - as HC would say - correct me if I'm wrong.

 

[WelshGas]

Not sure that there is any risk to braking here. I'm pretty sure that the interaction between the van and trailer for disabling sensors is electrical - not mechanical. So the only risk is that the brake lights on the trailer may not work.

But - as HC would say - correct mid I'm wrong.

When a VW Tow Bar is fitted and coded a few things are set up besides just the lights.
Trailer lights function - by law, and indicator function.
Cancelling Reversing Sensors.
Adjusting ESP function to compensate.
Adjusting Braking distribution front/rear.

 

[DM]

Cancelling Reversing Sensors.
Adjusting ESP function to compensate.
Adjusting Braking distribution front/rear.

Ah - so it makes electronic adjustment to the brakes - thanks WG. So what impact does that have when I'm using a tow-bar mounted cycle rack? A bit more weight further back but but nothing like the impact of a trailer.

 

[WelshGas]

Ah - so it makes electronic adjustment to the brakes - thanks WG. So what impact does that have when I'm using a tow-bar mounted cycle rack? A bit more weight further back but but nothing like the impact of a trailer.

No idea. But the nose weight , downforce weight, would be increased by about the same as the trailer weight is supported by its own axle and , if heavy enough, braked by its own braking system.

 

[DM]

No idea. But the nose weight , downforce weight, would be increased by about the same as the trailer weight is supported by its own axle and , if heavy enough, braked by its own braking system.

Sometimes it all just gets a bit too clever.

 

[WelshGas]

Sometimes it all just gets a bit too clever.

Too true.

 

[sidepod]

No idea. But the nose weight , downforce weight, would be increased by about the same as the trailer weight is supported by its own axle and , if heavy enough, braked by its own braking system.

Braking system could be altered via a ride height dependant valve mounted between rear axle and body, as per T4? Vertical load on tow ball altering rideheight slightly.

 

[B J G]

I had my 750kgs trailer on today and that has virtually no noseweight, you can lift the front with a couple of fingers so not as heavy as a bike carrier in that respect.

I did notice that the rear proximity sensors were off as was the reversing camera, not so good as I could see it in both my previous Discovery & BMW cameras.
I get no view of the trailer in the mirrors in the straight ahead position.

I didn't check if the 13 to 7 pin adapter alone cut the sensors off. Try it tomorrow.

 

[WelshGas]

I had my 750kgs trailer on today and that has virtually no noseweight, you can lift the front with a couple of fingers so not as heavy as a bike carrier in that respect.

I did notice that the rear proximity sensors were off as was the reversing camera, not so good as I could see it in both my previous Discovery & BMW cameras.
I get no view of the trailer in the mirrors in the straight ahead position.

I didn't check if the 13 to 7 pin adapter alone cut the sensors off. Try it tomorrow.

Must have changed on the T6 then as only the Reversing Sensors are disabled on my T5.1.

 

[DM]

Must have changed on the T6 then as only the Reversing Sensors are disabled on my T5.1.

Yup - I also lose the reversing camera - which is a pain.

 

[WelshGas]

Yup - I also lose the reversing camera - which is a pain.

One up for the T5 then.

 

[MurrayR]

Can anyone confirm that the comments above are relating to a 2007 model?
Just picked up the van from the dealer and they said there was no provision on the 2006, 2007, 2008 ,2009 models to connect to the diagnostic interface/gateway except for the on board power supply (Lamp monitoring?).
I find it hard to believe an imported California would be much different to the UK models you all talk about.

 

[Amarillo]

Yup - I also lose the reversing camera - which is a pain.

My reversing camera works, but not the rear sensors.

 

[WelshGas]

Can anyone confirm that the comments above are relating to a 2007 model?
Just picked up the van from the dealer and they said there was no provision on the 2006, 2007, 2008 ,2009 models to connect to the diagnostic interface/gateway except for the on board power supply (Lamp monitoring?).
I find it hard to believe an imported California would be much different to the UK models you all talk about.

There were different software protocols in use about that time for communicating with the onboard electronic modules. It might be that the garage in question is not aufait with this and may not have the necessary equipment/software. Is it a main Dealership?

 

[sidepod]

Sounds like bollox to me!

 

[rod_vw]

I would suggest a word with PF Jones who supply Westfalia tow-bars for T5 & T6, they will know what facilities are / were available on your 2007 model and which tow-bar electrics kit they would have supplied.

I have just fitted one of their kits to a new T6 and that has a loom that includes a module that interfaces with the BCM (Body Control Module) and needs to be coded to the vehicle which I did with VCDS. If your 2007 T5 should have such a module anyone (on this forum or otherwise) with VCDS can check if it is there and has been correctly coded.

Rod

 

[AlanC]

Can anyone confirm that the comments above are relating to a 2007 model?
Just picked up the van from the dealer and they said there was no provision on the 2006, 2007, 2008 ,2009 models to connect to the diagnostic interface/gateway except for the on board power supply (Lamp monitoring?).
I find it hard to believe an imported California would be much different to the UK models you all talk about.

Your dealer may well be right.

I can't see any tow bar Canbus wiring for a VW T5 built before 2009 listed on the PF Jones site.
http://tinyurl.com/mpjjmv5

nor on the Right Connections site
http://tinyurl.com/n8aeqq4

Alan

 

[rod_vw]

Month 10/2009 introduction of the face-lift T5 (T5.1)? I can't remember for certain.

Rod

 

[AlanC]

Yes, think that is right.

Mine was built early 2010 and first registered in March 10. The EGR was dated Dec 09. The tow bar wiring from Right Connections I fitted was for a 2009 van.

Alan

 

[jts46]

I had a tow are fitted in 2007 on my Cali by a company near Atherstone, Warks. Had no problems with it. Witter tow bar and cost £185 all in. No special loom needed.