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Discussion Starter #1 (Edited)
I installed LED Tails with a rear fog a couple of days after taking delivery of the Golf R. I figured I'd write up a few notes which other owners might find helpful.

I benefitted from all the information in the MkVI Golf/GTI forum about this. This isn't a DIY - most of the information you need with great pictures is already available in the MkVI forum. These are just some clarifying notes.

First thing - if you bought, or are buying, a Golf R (or really any modern VW or Audi), you should order Ross-Tech's VCDS tool. These cars have so many controllers, I can't imagine owning one of these cars without this tool. If you plan to do any kind of modifications, or even if you keep your car stock, at some point you will need/want this tool to see what's going on or troubleshoot something. Don't bother waiting until you need the tool - just go get it now. It will pay for itself very quickly.

Disclaimer - this is what I did on my car (which was obviously one of the first US Golf Rs produced) - your mileage may vary. Mod at your own risk. Second thing is that I've only driven the car briefly since I made this mod. So far everything (apart from one very minor issue below) is good, but faults could still turn up.

My goal was:
- keep LED DRLs
- add parking light function
- add rear fog
- add LED tails.

Part numbers I used:
(2) repair wires, 000-979-009E
(1) euro-switch, non-AUTO, chrome trim: 3C8-941-431Q XSH*
OEM Hella LED Tails (5K0-945-093AJ, -094AJ, -095Q, 096Q)
4 wire harness adapters for the tails (from ECS)

* see note 3 below - this is not the right switch for a US Golf R - the correct switch is 3C8-941-431B-XSH.

Summary of the steps I took:

- Installed wire from headlight harness pin 3 to T52/A pin 19 to enable the parking light signal.
- Installed wire from headlight harness pin 7 to T52/A pin 17 to enable the rear fog signal
- Installed European LED tail lights with rear fog
- Removed grey wire with white stripe from pin 28 of T52/A.
- Removed blue wire with green stripe from pin 47 T52/C.
- Switched the positions of these two wires so grey wire with white stripe is in 47 of T52/C
and blue wire with green stripe is in 28 of T52/A
- Recoded Central Electronics Module byte 18 from 0x20 to 0x04.

(Note: T52/A is the black connector on the CECM under the dash. T52/C is the brown connector).

Functionality I have now with headlight switch (w/ ignition on):

Off position: DRL running lights at correct intensity with DRL icon on cluster.
Parking position: DRL running lights dimmed (no cluster DRL icon), parking lights and tail lights on.
Headlight position: DRL running lights dimmed (no cluster DRL icon), parking lights, tail lights, headlights on
Rear fog position: works with switch in headlight position, also illuminates rear fog icon on cluster.
Single rear reverse light functions.
Brake lights function.
Turn signals ok.

Because I used the wrong headlight switch initially, I ran into one minor problem - attempting to activate the rear fog with the headlight switch in the "parking lights" position results in a fault code being generated, the rear fog not turning on, and the headlights turning on. I believe the headlights turn on because the fault code is generated (as a fail safe), although this is just my theory. The CECM is unhappy that the rear fog is being activated without any front lighting (no headlights, no fogs). Using the correct headlight switch will eliminate this issue because you physically cannot turn the rear fog on unless the headlights are on.

Other notes:

1. In the other forums you will see a lot of discussion about not being able to read the value of byte 18 in the CECM. In older cars, this value was displayed as "00", although its real value was something else. In the US Golf R, you can now read the current value of byte 18 which makes life much easier. Stock setting was 0x20.

2. The MkVI forum original post suggests disconnecting the wire in pin 47 T52/C and taping it up. And then moving the wire from pin 28 of T52/A over to position T52/C pin 47. This may have worked on older and/or halogen cars, but for my car with LED DRLs, you actually must swap these wires. It appears the wire in pin 47 is connected to the right front DRL and after you recode the CECM to enable the rear fog, pin 28 now controls the right front DRL.

3. The Golf R does not have front fogs. So the euro-switch I bought which has a front fog position is wrong switch for the car. The correct switch for the car is 3C8-941-431B-XSH, which has the rear fog position, but does not have front fogs. Also, this switch is available through US VW dealers - it is stocked in US distribution centers - you should be able to get one in a day or two.

4. ECS Tuning has install instructions on their website under the euro switch for activating the rear fog. These instructions have some nice pictures which are helpful, but unfortunately the information is wrong. They have you wire pin 3, which is the parking light signal - it will do nothing for the rear fog, at least on the Golf R.

Anyhow - thanks to all the people who worked on this stuff on the other MkVI cars - the DIYs in the MkVI forum are excellent, and I know people like Dana from Ross-Tech put in many hours sorting our wiring and coding issues previously.
 

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.....attempting to activate the rear fog with the headlight switch in the "parking lights" position results in a fault code being generated, the rear fog not turning on, and the headlights turning on. I believe the headlights turn on because the fault code is generated (as a fail safe), although this is just my theory. I don't believe this issue is wiring related - I suspect it *may* be due to the CECM being unhappy that the rear fog is being activated without any front lighting (no headlights, no fogs).....
As rear (and front) fogs would only correctly be used with the headlights/taillights on, it would seem your setup is correct, if it works correctly with the headlights/taillights on.
 

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FV-QR

My euro switch part number is: 3C8 941 431 C

I am not throwing any codes or anything at the moment, however I don't have the LED's yet either.



How many different versions are there, any what makes them different?
 

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What error is it throwing? I wonder if it's related to the absence of the front fogs and you having to go through that position to get to the rear fog.
the switch should have nothing to do with codes being thrown bc in cars without rear fog when the switch is pulled out to the second position there is no issue.
 

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the switch should have nothing to do with codes being thrown bc in cars without rear fog when the switch is pulled out to the second position there is no issue.
That's because there's no trigger wire for the fog to tell the ECU to light it. I don't know in the R if there's the wire for fogs or it's used for something else and that's what's doing it. It'd be good to know what code he's throwing.

My Golf R euro switch should be here late next week or early the following. I ordered it from tmtuning.com. Unfortunately the switch is going to beat my car here. :banghead:
 

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That's because there's no trigger wire for the fog to tell the ECU to light it. I don't know in the R if there's the wire for fogs or it's used for something else and that's what's doing it. It'd be good to know what code he's throwing.

My Golf R euro switch should be here late next week or early the following. I ordered it from tmtuning.com. Unfortunately the switch is going to beat my car here. :banghead:
I bought mine from TMT also. rear fog only.

the coding for the car doesn't support front fogs so it shld be ignoring that switch position.
 

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Which Ross-Tech are you using? Also, what is the preferred choice? What do most people use?
 

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Discussion Starter #15 (Edited)
I ordered the correct switch (rear fog, no front fogs, non Auto, chrome trim) for the Golf R from TM Tuning. They have it as their part number EP400-2. I haven't received it yet, so I can't 100% confirm its right, but they said it should be.

The fault code is a "light switch - implausible signal" fault. My theory is that the CECM doesn't expect to receive a signal to turn on the rear fog when no front lights are on.

I'm wondering if the correct switch with only the rear fog position requires you to turn the switch to the "headlight on" position before it will pull out to activate the rear fog. If so, you'd never see this issue. (There is no problem activating the rear fog from the "headlights on" position).

The switch I have is for a car with front and rear fogs. In a car with both front and rear fogs, its ok to turn on the rear fog from the "parking lights" switch position because this will activate the front fogs too. But in the Golf R there are no front fogs (or signal from the switch to turn them on), so when you're in the parking position and pull the switch out to turn on the rear fog, the CECM sees this and goes "wait! we're supposed to have the front fogs or headlights on" and throws an error. It doesn't really make sense to turn on a rear fog without some kind of forward lighting.

If anyone has a euro switch with a rear fog only (no front fogs), it would be interesting to know if you can pull that switch out to turn on the rear fog when the switch is in the parking lights position.

This is only a theory which I made up based on what I might engineer - I may be way off base. Other theories are welcome.

Sorry if this is a bit confusing/long. The good news is that this isn't really a big deal, although I would like to sort it a bit more.
 

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Can yopu post some pics with the Led tails installed?
 

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Discussion Starter #19
Can yopu post some pics with the Led tails installed?
Sorry - don't have one handy now, although if you look in the LED Tails thread on page 3, 98DUB posted a really good picture showing the smoked and cherry red tails. Mine happen to be the smoked ones. For reference - the stock US lights that come on the "R" are pretty close in color/tint to the LED smoked ones.
 

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Sorry - don't have one handy now, although if you look in the LED Tails thread on page 3, 98DUB posted a really good picture showing the smoked and cherry red tails. Mine happen to be the smoked ones. For reference - the stock US lights that come on the "R" are pretty close in color/tint to the LED smoked ones.
think ppl are just looking for pics of them actually on a US Spec R.

Here's a pic of the tinted R tails on the Euro car VW had at SoWo.


DSC_0276 by vwdork, on Flickr
 
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