Tow Bar Electrics - Caravan battery charging

Legacy_user

Does anyone have any first hand experience of adding the required connections for caravan battery charging / fridge supply - to the factory fitted towbar 13-pin socket provided by Audi ?

The Audi dealer has informed me that they would charge me more than £400 to provide the wiring kit and fit it, because the job takes several hours for their mechanic to complete.

I could do the work myself, if Audi would provide me with some wiring details, but I do not want to invalidate the 3 year warranty and I am a little worried that the standard "split charge relay devices" will not be suitable for a new Audi which has the advanced power management features.

mikey72

I can't speak specifically for Audi, but normally it involves re-programming the ecu so the car knows it has a split charger, and as you say, it's not the old style split charger anymore, so no longer a diy job.
It is surprising it's not already enabled on a new car with a factory fitted towbar though, I would have expected it to be "fit for purpose" without having to pay more.
Having said that, VW Audi have always supplied as base a vechicle as possible, and charged through the nose for any extra.

Gloomendoom

I don't know a lot about Audi's but I've recently done it on two cars (with canbus electrical systems.) In neither case did any ECU need reprogramming.

If it is just the extra charging bits that you need to fit, it can be done quite cheaply. You just need some appropriate wire, fuse holders and a self switching dual charge relay. If you wire this direct to the battery and thence to the 13 pin plug, the car will be unaware that it exists.

If you are worried about the warranty, then the only way to go is to fit a genuine Audi wiring kit.

The job is a lot easier if the battery is in the boot and can be done in a couple of hours. If the battery is under the bonnet then safely routing the wires can be a real pain. In the last car I did, it involved removing the rear seats and most of the plastic trim down one side of the car as well as the wheel arch liners and sundry other parts. I also needed a soldering iron and various other parts not supplied in the 'plug in' factory kit.

Edit: Be aware that disconnecting the battery for more than a moment can result in sensors needing to be reset. Make sure you know the radio code too, if it has one.

System

mikey72 wrote: »

I can't speak specifically for Audi, but normally it involves re-programming the ecu so the car knows it has a split charger, and as you say, it's not the old style split charger anymore, so no longer a diy job.
It is surprising it's not already enabled on a new car with a factory fitted towbar though, I would have expected it to be "fit for purpose" without having to pay more.
Having said that, VW Audi have always supplied as base a vechicle as possible, and charged through the nose for any extra.

I have raised that specific point with the dealer and also directly to Audi UK, I pointed out that the towbar with 13-pin electrics costs £665 and it is a UK specification car so should be supplied to UK specifications. No joy with the dealer, still waiting for a response from Audi UK but I'm not holding out much hope of them doing the extra wiring for free.

poppasmurf_bewdley

It won't have been the factory that fitted the Towbar and the current electrics. It would have been the dealer who supplied the car. Surely they should have done the job properly from the outset and that would include a connection for the fridge/battery charging.

I had a national mobile fitter fit towbar and electrics to my Mondeo Mk4 in September and it cost £295 for everything, and that car has all the problems associated with blown bulb display, etc.

Gloomendoom

poppasmurf_bewdley wrote: »

It won't have been the factory that fitted the Towbar and the current electrics. It would have been the dealer who supplied the car. Surely they should have done the job properly from the outset and that would include a connection for the fridge/battery charging.

I had a national mobile fitter fit towbar and electrics to my Mondeo Mk4 in September and it cost £295 for everything, and that car has all the problems associated with blown bulb display, etc.

It seems quite common for factory fit 13 pin wiring to be only equivalent to the standard 7 pin trailer socket... as my friend found out when he hitched his caravan to his new Ford Kuga. It resulted in quite a few heated exchanges between him and Ford. Eventually, they paid for the upgrade.

System

poppasmurf_bewdley wrote: »

It won't have been the factory that fitted the Towbar and the current electrics. It would have been the dealer who supplied the car. Surely they should have done the job properly from the outset and that would include a connection for the fridge/battery charging.

I had a national mobile fitter fit towbar and electrics to my Mondeo Mk4 in September and it cost £295 for everything, and that car has all the problems associated with blown bulb display, etc.

I have not taken delivery of the new car yet, so I am still negotiating to get it done.
But, I believe in most cases, today, with new cars, factory fitted towbar means exactly that, fitted at the factory as the car is being built. With modern car electrics, it becomes more difficult for after market tow bar companies to wire the 13-pin sockets because of all the modifications needed to the car systems. Things like :

• Reversing sensors, cameras, etc.
• Rear Fog lights
• Anti skid ESP systems
• Automatic gearbox programme changes
• Dynamic suspension programme changes (maybe)
• Power management which reduces load on battery when the charge is low

The above means that the socket wiring must be sourced from the correct place and also modifications are required to the on board computer so that the car systems know when a caravan / trailer is attached.


However, it seems that many car manufacturers omit the UK caravan charge / fridge connection, but that fact is not clear enough in the brochures when you buy a new car. (In the case of Audi at least)

poppasmurf_bewdley

I can't begin to imagine how much Audi and other car companies charge for a 'factory fitted' towbar and electrics.

Maybe you should Google mobile towbar fitters and get some quotes which you could use as a bargaining tool in your negotiations with Audi.

System

poppasmurf_bewdley wrote: »

I can't begin to imagine how much Audi and other car companies charge for a 'factory fitted' towbar and electrics.

Maybe you should Google mobile towbar fitters and get some quotes which you could use as a bargaining tool in your negotiations with Audi.

It costs £665 from Audi plus an extra £400 minimum for the dealer to provide the caravan charge connections.

It's not cheap, but it's removable, and when it's removed and the electric socket is folded away, there is no outward sign that the car has a towbar fitted, so it is worth having it done at the factory just for that reason alone.

But, there is also the added benefit that I do not have the risk of impacting on the 3 year warranty if an after market fitter did something that was not in accordance with Audi's specifications. This is why I am still asking the Audi dealer questions about impact on the warranty if I was able to do a DIY job or if an after market fitter added the extra connections.

At this point, I am not aware of any DIY kit that is available, hence the reason for this thread. But, also, I am not 100% sure that the after market towbar electric companies can provide the additional connections without effecting the warranty.

I was hoping that another MSE member may have already been through this process and found some answers to my questions, I still live in hope

Gloomendoom

BAA1 wrote: »

I have not taken delivery of the new car yet, so I am still negotiating to get it done.
But, I believe in most cases, today, with new cars, factory fitted towbar means exactly that, fitted at the factory as the car is being built. With modern car electrics, it becomes more difficult for after market tow bar companies to wire the 13-pin sockets because of all the modifications needed to the car systems. Things like :

• Reversing sensors, cameras, etc.
• Rear Fog lights
• Anti skid ESP systems
• Automatic gearbox programme changes
• Dynamic suspension programme changes (maybe)
• Power management which reduces load on battery when the charge is low

The above means that the socket wiring must be sourced from the correct place and also modifications are required to the on board computer so that the car systems know when a caravan / trailer is attached.


However, it seems that many car manufacturers omit the UK caravan charge / fridge connection, but that fact is not clear enough in the brochures when you buy a new car. (In the case of Audi at least)

Like I said, if you have the factory trailer wiring fitted, the extra wiring just to provide full caravan electrics is not technically challenging and, if you use the appropriate intelligent switching relays, will not interfere with any of the systems you have outlined above. It is essentially permanent live and a switched live with corresponding earth returns.

sunshinetours

Same issues with BMW's and dealers ask a fortune for fitting of OEm equipement and then often sub it out to motore electricians. many European's only use trailer electrics on their caravan/trailers etc so often the full 13 pin connection is not fully wired up

They wanted over £1200 for a Westfalia detacheable and new rear bumper section (so its hidden completely like yours)

Sourced all OEM parts and got several quotes from local tow bar specialist to fit and got it all for less than £700

I would also only use Audi approved wiring kits. often these cars (teh BM's especially) have inteliigent baterry sensors and all sorts of faults can appear if you don't use the right kit. Maybe try specialist Audi forums?