Towbar wiring question by Newbie to the forum.

[Cherryville]

Hello guys, thanks to Admin. for allowing me to join your Forum.

I have recently purchased a 2017 2.0 tdi  5 seat SE L manual 4x4  Kodiaq and will be fitting a towbar to it very shortly. My question relates to the wiring of the towbar to the car. 

In the past I have always fitted and wired the towbar to my cars, including those with can buss wiring requiring a 'smart box'.

Is the Kodiaq wiring different in any way that will not allow the purchase of a £50 bypass relay kit from Ebay to be used ?

I have noted from their contents there is only sufficient cable to extend to the rear light clusters where connections are assumed to be made.

All I want is basically the trailer lights to work as required and without possibility of damage to the cars electrical system. 

My car does have parking sensors but no reversing camera. Is there the facility to turn off the parking sensors while I have my trailer attached to the car, or has anyone retrofitted a system to allow them to be silenced while the trailer is being used ?

Thanks in advance to any responses which will be greatly appreciated.  

[SurreyJohn]

The simple answer is everything should be properly coded and not bypassed, it is not just parking sensors, if have any of reverse camera, ACC, blind spot monitors etc then they can all be affected.   There is no turn off switch so has to be coded to react differently when it detects a trailer is plugged in.

 

The days when cars had negligible safety systems and could just fit simple wiring are long gone

Edited 17 October, 2023 by SurreyJohn

[J.R.]

7 hours ago, Cherryville said:

Is the Kodiaq wiring different in any way that will not allow the purchase of a £50 bypass relay kit from Ebay to be used ?

 

No the relay will do what it is supposed to do without affecting the bulb failure test circuit, mine has been working fine for over 3 years now although it was a lot cheaper than £50.

 

7 hours ago, Cherryville said:

My car does have parking sensors but no reversing camera. Is there the facility to turn off the parking sensors while I have my trailer attached to the car, or has anyone retrofitted a system to allow them to be silenced while the trailer is being used ?

 

Just live with it if indeed it happens, my MK2 Octavia which I also used the high impedance switching relay on had parking sensors but the drawbar of trailers be they straight or Vee never triggered them, it might have had I jack-knifed it and got close to damaging the rear corner, in that circumstance I would want the sensors to work.

[J.R.]

1 hour ago, SurreyJohn said:

The days when cars had negligible safety systems and could just fit simple wiring are long gone

 

Not for me they aren't!

 

Although the days when you could speak of it on the internet without pressing peoples buttons (who were relieved of lots of money) have gone.

[Cherryville]

3 hours ago, SurreyJohn said:

The simple answer is everything should be properly coded and not bypassed, it is not just parking sensors, if have any of reverse camera, ACC, blind spot monitors etc then they can all be affected.   There is no turn off switch so has to be coded to react differently when it detects a trailer is plugged in.

 

The days when cars had negligible safety systems and could just fit simple wiring are long gone

Only has the parking sensors.

[silver1011]

Just fit a proper system. One that turns off the rear fog light on the car to prevent dazzle / reflection from off the front of the trailer, that deactivates the reverse parking sensors, that triggers the alarm if the electrical plug is pulled whilst the car is locked, that tells the cars braking system that it’s towing, shows the status of the trailers indicators on the dash, facilitates the use of LED trailer lights and enables additional features in the sat nav.

 

The days of splicing into the rear lights are long gone.

[J.R.]

22 minutes ago, silver1011 said:

The days of splicing into the rear lights are long gone.

 

On 17/10/2023 at 20:56, J.R. said:

Not for me they aren't!

 

The OP asked a specific question and it wasn't please order me what to do.

[silver1011]

On 19/10/2023 at 21:30, J.R. said:

 

 

The OP asked a specific question and it wasn't please order me what to do.

Again, in English?

[J.R.]

Sorry, not biting.

[Cherryville]

Hi guys, I was not expecting, or wanting, any heated discussion when I asked my original question.

 

I have purchased my new towbar with the recommended electrics, wiring and 'smart box' from my trusted local 'Motor Factors'.

As previously stated the supplied wiring is obviously designed to just extend to the the rear corners of the boot. There are no long lengths supplied to facilitate going to the cars dash area. 

I do not have a rear camera fitted, just the parking sensors in the bumper which will not be a concern as I will only be occasionally using my 6' X 4' trailer. 

[J.R.]

You will have no problems, the transistorised switching units (nothing "smart" about them!) are far better and more reliable than their predecessors, no more spacing of wire coils to get the audible warning working half correctly and they take so little load from the monitored circuit that they dont trigger bulb failure warnings.

 

The only thing to be aware of is that they are powered all the time even with the ignition off, this is in case you leave parking lights or hazard warning lights on, the quiescent load of the unit will slightly reduce the time your vehicle can remain unused before restarting becomes a problem, my first one used 25ma, the latest 15ma but in any case I fit a switch to disconnect it if I know the vehicle will be left for a long time.

 

Good luck with the fitting, power can be drawn from the accessory socket in the boot, the unit housed behind it in the rear corner close to the tail light, only two wires are needed to go to the other side for the indicator and rear light, even the latter is optional. Nothing to run to the front of the vehicle.

 

The audible beep for the indicators changes tone when the brake or rear lights are operated, once you know that you can verify that all the trailer lights are working from the drivers seat.

Edited 23 October, 2023 by J.R.

[Avocet]

On 23/10/2023 at 08:39, Cherryville said:

Hi guys, I was not expecting, or wanting, any heated discussion when I asked my original question.

 

I have purchased my new towbar with the recommended electrics, wiring and 'smart box' from my trusted local 'Motor Factors'.

As previously stated the supplied wiring is obviously designed to just extend to the the rear corners of the boot. There are no long lengths supplied to facilitate going to the cars dash area. 

I do not have a rear camera fitted, just the parking sensors in the bumper which will not be a concern as I will only be occasionally using my 6' X 4' trailer. 

As others have said, the modern cars do a whole lot more than just lights.  Perhaps the single most critical thing, is that if it detects a trailer , it runs a different Electronic Stability Control programme - which among other things, will gave you some anti-snake  protection.  Fr us, it simply wasn't worth the risk.  Not having the parking sensors going off all the time, not having the car's foglight reflection irritating you, and the blind spot detection sensors always being activated, was just icing on the cake!