dedicated or generic wiring?

Sep 19, 2020
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Hello all,

Need some advice, I have bought a 2017 Hyundai Santa Fe that will tow a 2006 Sterling Jewel with 2x 7 pin electrics.

The car needs a tow bar fitting. I am leaning towards a detachable swan neck with 13pin connector. My question is do I go for dedicated or generic wiring? Besides the increase in cost what will I get from dedicated wiring?

thanks in advance.
 
Jun 16, 2020
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I would also wire your two 7 pin plugs into one 13 pin. It is a more positive connection and simplifies the wiring. If you search it is possible to purchase a 13 pin plug that accommodates the two input wires through a special grommet. But it is possible to use a standard plug if care is taken.

John

PS, Here is is a conversion plug.

 
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May 7, 2012
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I was told that some car makers will not pay guarantee claims if you do use their own wiring system. I have not heard of any problems though with this so it is not easy to be sure how they react.
Personally I would fit the two nine pin plug system on the car as fitted to the caravan as the easier option but it is a matter of opinion.
 
Nov 6, 2005
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I was told that some car makers will not pay guarantee claims if you do use their own wiring system. I have not heard of any problems though with this so it is not easy to be sure how they react.
Personally I would fit the two nine pin plug system on the car as fitted to the caravan as the easier option but it is a matter of opinion.
Salesmen often say that - in reality, the warranty would only be affected if the towing wiring caused a specific problem.

2x 7-pin sockets on the car may be easier but they're less reliable connections than the 13-pin.
 
Mar 14, 2005
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Whilst I agree in principal with RogerL, the situation is, or has, changed:- In times past it was readily possible to differentiate all the systems in a car and it was clear that, for example: the windscreen wipers had no effect on the transmission or vice versa, but these days with a lot of car wiring and systems being controlled by a canbus system, it has given manufacturers lots more ways to blur the traditional segregation of systems, and now on some vehicles if you select reverse it causes the rear window wiper to operate! (by design)

This is all usually achieved by software, and unless you have access to the source code, and you can understand it, who knows how fitting a non approved towbar wiring harness might affect other systems in the car.

In the not to distant future, the car industry will be moving towards drive by wire for all systems in cars, and that could open up a much wider range of possible unforeseen critical interactions. Hopefully the manufacturers will have fully researched and designed out any dangerous issues, but who's to say an aftermarket unapproved towbar wiring harness or poorly fitted harness will not affect the braking system?

I think it's the sort of thing manufacturers will take great effort's to prevent, but even car manufacturers can be fallible.
 
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Reactions: Madpad_01
Jun 16, 2010
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From what I've seen in the past, non dedicated wiring tends to be not much more than splicing into the wires in the light clusters via a bypass relay.

My sister in law had a towbar fitted last year, not only did she get scotchlock connectors and a bypass relay, the 12V power she paid extra for was wired directly to the 12v accessory socket in the boot !

I'd always go for dedicated wiring, always going to be more reliable
 
Nov 30, 2022
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Dedicated wiring loom every time. A generic loom could cause issues, modern vehicles are far too complex to risk messing up the ECU. It might cost a bit more, but at least yiu know it won't interfere with anything on your car.
 
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Jun 16, 2020
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Out of interest I just looked up the PJ Jones options. The only do a dedicated option for the 2017 Santa Fe. For £173.32. No coding required.


They are not difficult to fit for someone reasonably handy and the fitting instructions can be downloaded from the same link. But personally I think the fitting charge is over the top.

John
 
Mar 14, 2005
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Professional fitting charges may seem excessive, but for anyone who is not familiar with good wiring practice, car electrics and how to fault find, the peace of mind of having it fitted by a "professional" provides a considerable comfort, knowing that if its doesn't work properly, the fitters can't wriggle out of their obligation to put it right at their expense and inconvenience, not the customers.
 
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Reactions: Mr Plodd
Jan 20, 2023
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Some (possibly the majority) of dedicated/plug-in wiring can enable the car to be "coded" to use the in-built towing features (stability programs, bulb failure etc) but NOT all. My previous car was a 2018 Volvo V90 and I had a PF Jones plug-in harness fitted and Volvo confirmed that they couldn't code the car to recognise the tow bar electrics as they could with an OEM system. I have no idea why but that was the story from two different dealers (Volvo Hinckley and Derby). On my new V90 I had the dealer fit a full Volvo system.
 
Nov 16, 2015
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2014 Santa Fe, I had a towbar and electrics fitted from new, it was Hyundai Part No. But Witter unit. Terrible fitment , kept dropping, ( Google problems) changed for a TowTrust unit. But the electrics were fine, I don't think there were any interlinks for the 2014 Santa Fe for towing. Maybe different for the 201ú.
 
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Some (possibly the majority) of dedicated/plug-in wiring can enable the car to be "coded" to use the in-built towing features (stability programs, bulb failure etc) but NOT all. My previous car was a 2018 Volvo V90 and I had a PF Jones plug-in harness fitted and Volvo confirmed that they couldn't code the car to recognise the tow bar electrics as they could with an OEM system. I have no idea why but that was the story from two different dealers (Volvo Hinckley and Derby). On my new V90 I had the dealer fit a full Volvo system.

Makes you wonder then. When PF Jones say ‘coding not required’. Do they really mean

Coding not NECESSARY and we can’t actually do it.

My Volvo was done by Volvo. I don’t know if they needed to do any programming as such. But when pluged in, the Stop Start function is turned off, And I think rear fog and reversing lights are cancelled.

It would be interesting to know what effect the PF Jones control unit would have.

4AB8E875-DCB1-4E37-938F-215F37A57A94.jpeg


John
 
Jan 20, 2023
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The PF Jones V90 loom I had fitted needed splicing (cut & connect) into the car loom for the fog light delete (everything else was plug in). Guess what? Volvo use the same colour wire (yellow/black from memory) for the fog lights and fuel gauge! We found out when checking the newly fitted tow bar and rather than the fog lights extinguishing the fuel gauge dropped to empty!!!!
 
Jan 19, 2002
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Much better to future proof with the 13 pin on the car altogether a much more reliable connection although it does mean you either have the caravan changed or use an adapter, again the former being the most reliable
 
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Nov 16, 2015
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I would go for a 13 pin plug and go for just an adaptor for the caravan.
Also on my Factory fit towbar and electric s, I still had to put in the extra earth for the fridge. Myself.
 
Nov 30, 2022
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I would check with Hyundai (head office customer service not your dealer) EXACTLY what the fitting of their factory supplied loom does or does not do to the systems on the car (fog light cancelling, stop start cancelling etc) and if the car will need reprogramming once fitted and then ask Jones to confirm in writing that the loom they fit will do exactly the same. That way if there are any issues you will have them over a barrel.
 
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Mar 14, 2005
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We have a Tow Trust bar fitted with Hyundai/Kia dedicated electric kit, fitted to 2021 Santa Fe, biggest problem fitting the wiring was removing and repalcing the boot trim, otherwise just plugged in and all good to go, van is Swift with Led lights and no problem in 2 years.I would always go 13 pin on both car and caravan, we used to get middle pin burn out when we had 2x 7 pin system, suspect the middle pin used to close up and make poor contact, can't happen with 13 pin plug
 
Jul 18, 2017
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It would seem that most vehicles are not designed taking towing into consideration. At least our 2018 Jeep did not require dedicated wiring although it has the facility to activate a trailer tow settings. We had the choice.
 
Jan 3, 2012
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When i got my car from a Volkswagen dealer i ask how much i be looking for a Detachable Towbar they said roughly £1,000 +
So i got a mobile fitter come to my home and he put a Westfalia detachable towbar and a 13 pin plug with a dedicated wiring loom and a life time warranty we paid £600
 
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Nov 11, 2009
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When i got my car from a Volkswagen dealer i ask how much i be looking for a Detachable Towbar they said roughly £1,000 +
So i got a mobile fitter come to my home and he put a Westfalia detachable towbar and a 13 pin socket with a dedicated loom and a life time warranty we paid £600
Probably the same fitter who would have done it for the dealership, unless VW install at the factory.
 
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Mar 14, 2005
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I would clarify Buckman's last comment. Ironically, Jeep are one company that almost certainly does consider towing as one of their important objectives for their vehicles, and there are several others mainly 4x4's. But certainly for most cars, towing is not their highest priority.

One of the comments we often see about the fitting of a towbar and wiring is how the caravan battery, and or the fridge are not wired as standard. There is often some consternation about this, but the reality is caravaning is a niche case, and the majority of trailers do not need a battery or have a fridge.
 
Nov 6, 2005
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It would seem that most vehicles are not designed taking towing into consideration. At least our 2018 Jeep did not require dedicated wiring although it has the facility to activate a trailer tow settings. We had the choice.
I'd dispute that, at least as far as European and Asian originated cars go - although it's certainly true for cars/SUVs of American origin as they regard them unsuitable for towing and everyone should get a pickup for towing duty.
 
Jul 18, 2017
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I would clarify Buckman's last comment. Ironically, Jeep are one company that almost certainly does consider towing as one of their important objectives for their vehicles, and there are several others mainly 4x4's. But certainly for most cars, towing is not their highest priority.

One of the comments we often see about the fitting of a towbar and wiring is how the caravan battery, and or the fridge are not wired as standard. There is often some consternation about this, but the reality is caravaning is a niche case, and the majority of trailers do not need a battery or have a fridge.

Our previous Jeeps were wired for the fridge, but due to the smart alternator the fridge did not operate correctly when connected to the car. At the time I was not aware of it being a smart alternator.

On our current Jeep the wiring was already in place for a normal trailer with no 12v feed for the fridge so we did not bother getting it connected up as seldom travel with food in the fridge to ensure we stay within the MTPLM. However I am not sure if the caravan battery would get charged when connected?
 

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