Factory Fit Tow Bar Electrics Not Working

[Wallaces Travels]

Being wise enough to know that not everything with a new VW doesn't always work, I've just hooked my new Cali with factory fit tow bar and electrics to my Caravan to discover that nothing on the 13 pin socket is working!

I also tried my trailer just to be sure it's not the van... the same.

Spoke to the supplying dealer who can look it at the end if March.! (How's that for aftercare with a premium product?).

Does anyone have a similar experience and discovered a quick remedy ?

 

[Meoncoast]

Being a new van and wanting to safely tow your Caravan / trailer I would just ring VW assist and say you need to move your van safely

 

[Wallaces Travels]

Being a new van and wanting to safely tow your Caravan / trailer I would just ring VW assist and say you need to move your van safely

Thanks for the advice. I did call VW assist who sent someone , but all they did was to test the main fuses under the bonnet. It was a general AA patrolman who didn't have any particular knowledge about VWs. (Not even the location of the other fuse "boards").

I'm waiting to take it to a main dealer. I suspect either a misconfiguration at the factory or a loom not connected, again, at the factory. Fortunately I don't need to tow for a couple of weeks. Today was the first opportunity I had to test the electrics since collecting the Cali.

 

[WelshGas]

Being wise enough to know that not everything with a new VW doesn't always work, I've just hooked my new Cali with factory fit tow bar and electrics to my Caravan to discover that nothing on the 13 pin socket is working!

I also tried my trailer just to be sure it's not the van... the same.

Spoke to the supplying dealer who can look it at the end if March.! (How's that for aftercare with a premium product?).

Does anyone have a similar experience and discovered a quick remedy ?

Please don’t take this the wrong way, but when plugging in the caravan/trailer you turned the caravan plug 90o clockwise?

When plugged in if you start the vehicle and engage Reverse, what do you see on the Media display?

 

[Wallaces Travels]

Please don’t take this the wrong way, but when plugging in the caravan/trailer you turned the caravan plug 90o clockwise?

When plugged in if you start the vehicle and engage Reverse, what do you see on the Media display?

Hi, any advice is welcomed. Yes , I did rotate to align the socket lid with the plug flat part. I started the engine to see if the charge/fridge circuit was working since nothing else was, but didn't try reverse. One strange thing though, when trying the indicators, the rear Cali blinker didn't light-up (but was fine after I disconnected). Also, just be sure the caravan wasn't causing the problem, I tried the caravan with another vehicle and all was OK.

 

[Rich20]

This might be a long shot but worth checking. I had a Skoda Superb with factory tow bar wiring and there was a connection block behind the trim panel in the boot space. In the Cali it might be where the Jack /RCD switch is located behind the near side removable cover. Might just be worth a look to make sure it’s plugged in properly if it’s there.

 

[Wallaces Travels]

Thanks for the advice. I've tried following the cables, but there are so many covers to remove.
The rear indicator not flashing was a red-herring (the indicator was switched-off by my assistant before I went to the rear of the vehicle ). I've tested all the fuses under the passenger seat (which is where the Trailer control modules fuses reside, also, with a meter, I tested the socket directly to eliminate any plug-socket issues. Still no power. That's about the limit of my diagnosis. The dealer has offered to have a quick look for anything obvious. Since it's a 100mile round trip and I would need to return to book a further appointment if there was "nothing obvious" , I've managed to book the Cali in to a main dealer in a couple of weeks. (Which should just be OK for my first towing outing).

 

[Ch1pbutty]

These are useful for fault finding..

MP1802B 13 Pin Car and Trailer Tester - Maypole Towing Accessories

MP1802B 13 Pin Car and Trailer Tester is suitable for testing ISO 11446/13 pin lighting & 12V power supply circuits. LED indicators clearly show any faults.

www.maypoleltd.com

 

[Devaprem]

I have a VW tow bar fitted after I bought the vehicle. The cable running to the rear 13 pin socket terminates at the other end in a multi way connecter that plugs into a in-line (cable mounted) socket under my driver's seat. That socket then connects to the vehicle electrics at the front via another wiring loom. It may be that your multi way connecter simply hasn't been plugged in to that socket. However, I don't know where VW put that socket when the towing electrics are factory fitted, it may be somewhere else other than under the driver's seat. If you have access to a tester like Ch1putty has posted you could check that you have (at least) the permanent 12v feed. Apparently this tester does require the caravan to be plugged in to the other socket on the tester (it cannot be used just to test either caravan or vehicle electrics alone). If the tester's LED for the permanent 12v feed on the tow socket doesn't light up, one possible reason may be that the rear wiring loom multi way connecter hasn't been plugged in to the in-line (cable mounted) socket .

Not totally related but may be of interest longer term - after some tow bar problems of my own, I decided to buy a DVLA approved tester: https://www.prosol.co.uk/product/13-pin-towbar-trailer-socket-tester-dvsa-approved-for-mot-use/ which I can recommend for just testing the vehicle tow bar electrics. Another thing I bought is a socket cover to reduce water getting into the socket (despite the cover on the towing socket, it does happen sometimes). https://www.maypoleltd.com/product/mp242b-pvc-socket-cover-2/. Fitting a lockable/unclockable cable tie round the back of the cover may be a good idea because mine was a little loose fit

 

[Meoncoast]

I think you are missing a trick with VW assist esp on such a new van. OK they sent you a standard AA patrol. I would ring again explaining pending towing holiday and ask for VW assist if they can not fix then they can get priority booking at van centre. OK you have a booking but parts alway seem on back oder so your booking may be cutting it fine.

 

[Wallaces Travels]

Thanks for all the suggestions. I have No lighting circuits, no permanent 12v and no ignition 12v which leads me to think that it could be a loom connection. I'll try VW directly again, possibly customer relations. I hope that they are better than Land Rover who ,when having problems with a new Discovery , told me that they do not sell cars and all aftersales is through the dealer network!

 

[Wallaces Travels]

Update: Just spoke to VW Customer Relations. Complete waste of time. They cannot send any particular specialist via VW assist neither can they influence the dealer network. The only suggestion was for me to phone around the dealer network and see who could fit me in the soonest!

When I asked what was the purpose of direct VW customer service ,the reply was that with this matter, very little !

Another example of appalling service-which is just too common these days.

Only other option is to escalate with the supplying dealers,Listers, and get a better response than a workshop slot in one month's time.

 

[Ch1pbutty]

Don’t take it to VW, take it to a local towbar specialist. They will most likely have seen the issue before and it will be an easy fix for them.

 

[Devaprem]

A small clarification to my earlier post: the in-line (cable mounted) socket under my driver's seat that I referred to may be what's called the 'Bypass Relay'. This does the job of translating the signals on the vehicles Canbus system (where more than one signal is carried down a single cable) into the caravan's simple one wire per function system for the caravans lighting. So, it may be that the rear wiring loom has not been connected the the bypass relay.

 

[Wallaces Travels]

Thanks for the clarification. I have also talked with my local tow bar fitter who installed an aftermarket electrics to my old T5 - he hadn't come across my current (no pun!) Issue before. Looking at the message from Ch1pbutty , I will try another tow bar specialist to see if they have anything to add.

 

[Wallaces Travels]

I thought that I'd provide an update. - Electrics now appear to be working !

I had a VW centre test the electrics and they were all OK. I returned home, plugged in my trailer and all lighting circuits worked !. Possible explanation - the VW Technician told me that there is a microswitch in the socket and maybe that was "sticky" ?

I have yet to test the Caravan, but I did some further testing at home with my trailer, and found the following -

1. With socket correctly inserted and no load (With a spare 13pin cable I have), the Cali did not detect a trailer. (So how does the Cali detect a trailer ? doesn't seem to be the microswitch - a load/resistance on one or more circuits would be the logical conclusion).

2. There is a delay between plugging in and Cali recognising trailer and powering the 12V used by the ATC and aux circuits.

3. With no trailer detected, the aux 12v feed and ignition sense feed for charger and fridge, have no outputs. When a trailer is detected, these circuits are also activated.


I hope that this feedback is useful.

 

[Devaprem]

Glad to hear they are working. The microswitch is for cutting out the vehicle fog lamp, reversing sensors and possibly the reversing light when a there a trailer or caravan plugged in. They aren't needed and light reflecting from those lights ig they are on can be distracting to the driver. I don't have a microswitch on mine and this is all managed the Canbus system so, assuming yours works in the same way, then your engineer's comment sounds incorrect.

In answer to you first question: I believe load, as you mentioned, will result in the trailer detection. Once I plug my Prosol trailer socket tester in, the display comes top on the screen and there's a load resistance across some of the pins in it's plug

I don't know the answer to 2 but would expect a short delay between plug-in and power. The ATC LED on A frame of my caravan lights up green when it is connect and there's a very short delay to that between plug-in and light up. Here's what the manual for my caravan says: "ATC will carry out an initial self test and the LED light on the front fairing will light up on RED. During the self test, the sound of the push rod moving inside the ATC can be heard. When the self test is complete, the LED will turn GREEN or flashing GREEN to signal that the ATC is active"

In the case of 3, again I don't know why but am not surprised by this from an electrical point of view. From a safety perspective, the less pins that have volts on them when disconnected from a socket that is partially exposed to the elements, the better. I do recommend the tow socket cover that I mention in my previous post. A tow bar fitting expert said that, even with the best cover that flaps over the socket, water always gets in eventually and may cause electrical problems.