Fitting external reversing lights to Golf 7

[Sbuddz]

Hi all!

First thing first
I have a 2016 Golf 7 SC with factory fitted trailer hitch and R-Line.
I´m just now fitting 2 external reversinglights wich will be flushmounted inside the "diffusor".

No problems with how to fit them to the car itselves, the problem starts with the electrics.
I want to connect the 2 external lights via a relay ( just to be safe ) so I need a signal from the original reversinglights and I was thinking, what better way to find that signal then on the cable for the trailer hitch.
It´s just that I dont get any signal at all when no trailer is attached. 0V in all 13 pins for the trailer.

I need your help with this.
The trailer hitch modul is 5Q0 907 383H
Is it possible to code it via VCDS so that I can get the reverselight signal even with no trailer attached?
Does anyone have a pinout diagram for this trailer module?
I do not know what colour the cable for reverselight have.


Soory for any bad spelling ( I´m swedish )

/ John

[Transporter]

When connecting via relay you can safely pinch the power from the reversing light at tail light. Choose relay with the coil with the smallest current and all should be good.

[DV52]

Hi all!

First thing first
I have a 2016 Golf 7 SC with factory fitted trailer hitch and R-Line.
I´m just now fitting 2 external reversinglights wich will be flushmounted inside the "diffusor".

No problems with how to fit them to the car itselves, the problem starts with the electrics.
I want to connect the 2 external lights via a relay ( just to be safe ) so I need a signal from the original reversinglights and I was thinking, what better way to find that signal then on the cable for the trailer hitch.
It´s just that I dont get any signal at all when no trailer is attached. 0V in all 13 pins for the trailer.

I need your help with this.
The trailer hitch modul is 5Q0 907 383H
Is it possible to code it via VCDS so that I can get the reverselight signal even with no trailer attached?
Does anyone have a pinout diagram for this trailer module?
I do not know what colour the cable for reverselight have.


Soory for any bad spelling ( I´m swedish )

/ John

John: hello and welcome to the forum. For obvious reasons, my understanding of the protocols that VW uses in Sweden for its trailer wiring isn't good, but I assume that your car has the standard EU 13 pin socket. If so- here is the pin-out diagram



However, if the socket is wired as standard, it will be powered by what VW calls J345 - which is the trailer detector control module.

As the name implies, nothing happens to any of the pins on the socket unless a trailer is detected! I suspect that this is the reason for your observation " I dont get any signal at all when no trailer is attached" - because it's the job of j345 to disable the socket when no trailer is attached to the car!

I also suspect that this is why it's probably not a good idea to get your +12v initiating signal for the new relay from the 13 pin socket

You could of course take supply from the back of the two existing reversing lights (in the tail-light assemblies). But if you don't want to access the hatch-door wiring, you might consider a lateral thinking alternative as follows:

1. the only permanently live wire in the 13 pin connector is pin 9 - regardless of the trailer's connection, this pin is +12 Volts.
2. Connect one end of the the normally-open contact terminal on the relay to this pin
3. connect the wires from your new reversing lights to the other end of the normally-open contact terminal on the relay
4. Buy yourself a 12 Volt remote control from eBay - the kind that is "momentary", not the "latching" kind
5. wire the receiver output terminal on the remote control to the coil of the relay - so that the relay is energized whenever the remote receiver operates
6. on the remote control transmitter, wire together the push button contacts so that the transmitter always operates when it receives power.
7. If you have chosen the remote control correctly, you would have purchased a transmitter that is powered by one of those small 12v batteries
8. In place of the battery on the transmitter, wire-in an electrolytic capacitor (size is unimportant, but around 100 micro-farads should do - and be careful of polarity on the capacitor) . The reason for the capacitor is to smooth-out the CAN bus signals that are superimposed on the reversing lamp supply (the CAN signals appear on a scope as negative-going pulses and they can interfere with the remote control transmitter)
9. Wire the positive terminal from the remote control transmitter to the positive wire on one of the reversing lights in the tail-light assembly - the negative terminal from the remote control transmitter should be earthed somewhere convenient. - Wrap the remote control transmitter in heat-shrink tubing and leave in the hatch somewhere suitable where it won't rattle.

So - the way this system works is that whenever you select reverse gear, the light in the tail assembly is energized as normal - but it now also energizes the remote control transmitter - because you wired the push button terminals together. This then energizes the remote control receiver which closes the contact on the new relay and powers your new reversing lights. Because the remote control receiver is non-latching (i.e. momentary), as soon as the reverse switch on the gear box is opened, the system shuts down - and there is no need to bring any wires out-of the loom in the hatch

I've used this set-up on a mk6 and it works OK

Don

[Sbuddz]

Thank you Transporter and DV52 for your answers.
I know I could get the signal from the original reverselights in the hatch but I´m to exited about doing the wireing from there

DV52
I know the pinout configuration for the 13 pin connector that I have, but there are as you pointed out know 12V current in any of these 13 pins without having a trailer attached, not even pin 9.

I have VCDS and I have done a few changes to my car using VCDS and the superior in this forum but I spend a couple of hours yesterday trying to figure out how to get signals out to the 13 pin connector without a trailer attached but I had no luck at all.
I should say that the trailer connector works perfectly when I have a trailer connected. All 13 pins are doing what they are suppose to do.

Regarding the remote control. I admire your skills when it comes to this, I found it hard to beleive that I could make it work

By the way, these are the light I´m going to hook up
Ignite | Backup Light Kit Flush White Black | Rigid Industries

/ John

[DV52]

Thank you Transporter and DV52 for your answers.
I know I could get the signal from the original reverselights in the hatch but I´m to exited about doing the wireing from there

DV52
I know the pinout configuration for the 13 pin connector that I have, but there are as you pointed out know 12V current in any of these 13 pins without having a trailer attached, not even pin 9.

I have VCDS and I have done a few changes to my car using VCDS and the superior in this forum but I spend a couple of hours yesterday trying to figure out how to get signals out to the 13 pin connector without a trailer attached but I had no luck at all.
I should say that the trailer connector works perfectly when I have a trailer connected. All 13 pins are doing what they are suppose to do.

Regarding the remote control. I admire your skills when it comes to this, I found it hard to beleive that I could make it work

By the way, these are the light I´m going to hook up
Ignite | Backup Light Kit Flush White Black | Rigid Industries

/ John

John: OK, my bad - on the mk6 that I applied my fix-to, pin 9 was live without the trailer connected. An alternative is to use the wire from the power socket inside the hatch (as the supply source for the NO contact on the relay)- The remote control solution wasn't a difficult circuit to build, but I understand if you are not confident in applying the technique.

Alas though, it means that you will need to run a trigger wire from the back of one of the existing reversing lamps, which I personally consider to be more difficult than using a soldering iron and fitting a few electronic components!

I'm also not sure that a VCDS cable will be much help - j345's specific purpose is to isolate the socket voltages without the trailer present - not sure that you can defeat such a fundamental function in the control module - but more than happy to be proven wrong!

Don

PS: nice lights - not cheap though!

[Sbuddz]

Nice lights dont come cheap, same as nice cars ( like mine )

I will stop by the local VW service place tomorrow and ask if and how it´s possible to have an +12V reverse signal somewhere with easy access.
Swedish police drives new Passat with external reverse lihts monted in a bad way under the rear bumper, I´ve also seen a few taxi´s with the same installation.

I´ll keep you posted on how I will make it work and post pictures when it´s all done.

/ John

[agentthumb]

Just chiming in from a safety perspective RE forcing the use of trailer connector. (Not saying that's what you are doing, but thought it's worth raising.)

If your car has trailer sway control built into the ESC, then activating the trailer module to send power to the socket will switch your ESC to this setting. This means your car has the potential to behave very differently when ESC kicks in during sudden manuvers wit no actual trailer attached.

[Sbuddz]

Good input Agentthumb, I did not know that.
I have come to the conclusion that I will contact my local VW dealer to get advise in this matter, maybe even let them do the job so that a have a wire somewhere that´s live with 12V when reverse gear is selected.
From there on it´s easy and I can manage on my own.

[Sbuddz]

All done!

I got the info i needed from my local VW dealer.
The signal I needed for my relay is easiest to get at the hinch between rear hatch and the car ( see the pictures )
The Connection is called T10K and at connector number 7 you will find a Black/Blue wire, thats the one.

I got the 12V supply from the rear 12V outlet and the relay for my new lights are located on the left side, just under the factory toolkit in the car.

It all worked out as I wanted it to, thank you for all your help, info and input.

[DV52]

All done!

I got the info i needed from my local VW dealer.
The signal I needed for my relay is easiest to get at the hinch between rear hatch and the car ( see the pictures )
The Connection is called T10K and at connector number 7 you will find a Black/Blue wire, thats the one.

I got the 12V supply from the rear 12V outlet and the relay for my new lights are located on the left side, just under the factory toolkit in the car.

It all worked out as I wanted it to, thank you for all your help, info and input.

Sbuddz: Great to hear that the project has been successfuly completed - well done!. I think that I understand how it was wired ultimately, albeit my wiring diagram is a little different - the pin7 connector (which feeds the left reverse light) on the coupling point on the rear lid (THK) is labelled 10d and the wire is white on my diagrams - see below



But I have another question that puzzles me. I had thought that the point of the relay was to not overload the trigger wire when you were considering the trailer socket option (good idea IMO). But, since you ultimately connected directly to the reversing lamp itself - why use the relay at all (with the added work of breaking into the 12Volt hatch socket)?

The additional lamps are LED type which are very efficient and each new lamp is only 12 Watts (i.e. < 1 amp @ a nominal rail voltage of 12.8 Volts) Given that you have gone to the trouble of breaking into the hatch wiring, why not run a cable from each reversing light on the coupling connector on the hatch lid and do-away with the relay and separate +12 V supply entirely? I doubt that the additional load on each reverse light would be sufficient to trigger a fault and even if it did, a simple modification to the 2 x Leuchte-sets for the reversing lights would fix the alarm.

Don

[Sbuddz]

Hi Don!
My bad, the connector is of course THK ( not T10K ) and it's pin 7 T10p, which is Black/Blue. I choose to get the signal from the T10d white cable because of space issues, but it's the same signal.
Regarding the Relay I have, it's just as a safety feature. The 20w (about 1.5 amp) would easily work without a relay, but I like relays 😜