Polo 6R --> 6C Tail Lights conversion: parking lights not working.

[Jay-Jay]

Hi everybody.
Today I've done the conversion to Polo 6C Tail Lights.
I followed the guide made by Ciclo and I made the adaptors by myself.
All bulbs work fine, except for the parking lights.
When I turn-on the ignition, the parking lights (front and rear) turn-on for 1 second and then they automatically turn-off and the check-bulb lamp appears on the instrument cluster.
I checked the adaptors wirings multiple times and they are correct.
I checked the fuses and they are all fine.
I tested the rear parking lights bulbs and they are fine.
Scanning with VCDS, these are the errors that come up as soon as I turn-on the ignition:

Address 09: Cent. Elect. Labels: 6R0-937-08x-09.clb
Control Module Part Number: 6R0 937 087 D HW: 6R0 937 087 D
Component and/or Version: BCM PQ25 H+4 H46 0207
Software Coding: 3CA02BB808210000003800003D2B9CD00F40672060840001200000000000
Work Shop Code: WSC 12345 123 12345
VCID: 3E738BFFA977BC7621-806A
2 Faults Found:

03431 - Activation of Left Parking Light
007 - Short to Ground - Intermittent
Freeze Frame:
Fault Status: 00100111
Fault Priority: 2
Fault Frequency: 1
Reset counter: 79
Mileage: 152303 km
Time Indication: 0
Date: 2036.14.02
Time: 15:37:11

03432 - Activation of Right Parking Light
007 - Short to Ground - Intermittent
Freeze Frame:
Fault Status: 00100111
Fault Priority: 2
Fault Frequency: 1
Reset counter: 79
Mileage: 152303 km
Time Indication: 0
Date: 2036.14.02
Time: 15:37:11

I reinstalled my old 6R Tail Lights and the problem disappears.
It seems like it is exclusively related to the parking lights only when I install 6C Tail Lights.
Could it be the BCM detects that the rear bulbs absorb more electricity (T15 16W compared to the T10 5W of the 6R tail lights) and it stops the electricity because it thinks it's not safe?

Any help would really be much appreciated.

[iichel]

What is your front parking light? LED? Xenon? LED?

[Jay-Jay]

Hi iichel! Thank you in advance for your help!
My front parking lights are the LEDs integrated into the OEM Bi-Xenon headlights.

[iichel]

I've seen this before. The power demand is growing too high with the W21W light and the bi-xenon headlight LED module powered by the parking light pin.
Your bi-xenon is probably connected with T14/12 and T14/10 to T10/10 of the original headlight, correct?

A possible solution is to put a relay between T10/10 and T14/10 and /12 or to move T10/10 to T10/1 (+15 for the headlight motor.
But in the latter case, you lose parking lights with ignition off at the front.

[Jay-Jay]

Yes, my front LEDs are connected in that way: T14/12 and T14/10 to T10/10.

So, the solutions are two:
1. install a relay between T14/10 and /12 and T10/10;
2. move T10/10 to T10/1.

Is that correct?

I'm not sure I completely understand the second solution.
If I move T10/10 to T10/1, what do I link T14/10 and T14/12 to?

[iichel]

Connect T10/1 to T14/10 and /12

[Jay-Jay]

Ah, ok!
I'll try that and let you know!
I don't care if I'll loose front parking lights with ignition off, so I think this could be the fastest solution for me.

[Jay-Jay]

Just to recap, so I'm sure I understood.
This is my actual front headlights connector wiring:


And I should change to this wiring:


Is that correct?

I have 2 other questions:
1- Will LEDs turn-on with ignition on? I'd like them to be on all the time at 100% brightness, like now.
2- Could I experience LEDs flickering while turning the steering wheel? I already had that problem at the start, but then I fixed it by modifying the BCM coding.

[ciclo]

My humble opinion:

On the 6R Europe models (2009-2014) with factory Bi-xenon headlights, the parking-side lights are individually powered from 4 different pins on the BCM (MAX models).
The BCM High as the one you have installed do not have the pins for the front parking-side lights, it uses only two pins to power each side, and it is the reason why your current lights setup experience such problem. (Bix + TL 6C)

Install a BCM Max, it is the easiest, fastest, cleanest and safest way to make all your lights work properly, any other option is a dangerous fudge.
You can omit many parts of the original installation, those that you consider appropriate, but they are simple cables and it is worth doing it in its entirety.
(many skipped the level sensor installation, automatic lights, rls, etc)

I have no doubt that you are an intelligent guy, therefore, the installation will be extraordinarily cheap, ... even more than if you do the cumbersome installation of the aforementioned relay, which is undoubtedly a fast but monstrous solution.

Look for a second hand BCM Max (7H0 or 7E0, even the most crappy BCM Max will get the job done ), you have my free assistance - coding, etc- if you do a simple installation (BCM and cables for it).
There is already a tutorial for this circumstance in which you are... well I think I did tutorials for all possible circumstances.


---
Note: I no longer manufacture wiring looms for anyone.

[Jay-Jay]

Hi ciclo! Thank you so much for your suggestions.
I totally understand that installing a BCM Max would be the best solution, but I found the 6C Tail Lights in mint condition at a very cheap price (almost free), so I don't know if I want to spend more money on them...
At the moment, I want to try moving the power source of the front LEDs from T10/10 to T10/1, as iichel suggested.
I think it's the fastest and cheapest (literally free) solution.
I hope there will not be any of the negative consequences I wrote above, otherwise I will consider to sell the 6C Tail Lights and keep my 6R ones.

Another solution I thought is to not touch the adaptor wirings of front headlight and to power the rear parking bulbs with a different source (plate lights signal? interior lights signal?). Any other source that turns-on with the ignition should be fine, as soon as it supports the power consumption of two W16W bulbs.

[Jay-Jay]

Well, I've just discovered that T10 bulb and T15 bulb have the same connector size, so it is possibile to replace the T15 bulb of 6C Tail Lights with a T10 bulb.


In this way I can install 6C Tail Lights without BCM errors, but rear parking lights are less bright than with 16W bulbs:


This is the final result:

I don't think it's bad, don't you?

Now, if I want brighter rear parking lights, I think I have 3 options:
1- find and buy a pair of very bright T10 RED LED bulbs, which only absorb 5w, but are bright as much as a 16w bulb or even brighter;
2- reinstall 16W classic bulbs and power them through another source which doesn't meet my BCM power limitation;
3- install 2 relay, one for each rear parking bulb.

[ciclo]

The simplest and safe solution for your current light setup is to install some powerfull LED bulbs (without resistors or anything related to CAN bus Error free) where the current bulbs (16w) for the rear parking-side lights are.
This will do the work you need.

This way you do not have to touch anything at all and will be almost free ...

[ciclo]

we were just posting at the same time ... forget my previous post ...

[ciclo]

...

Now, if I want brighter rear parking lights, I think I have 3 options:
1- find and buy a pair of very bright T10 RED LED bulbs, which only absorb 5w, but are bright as much as a 16w bulb or even brighter;
...

I guess you don't need to buy the RED LEDs, buy them white.

[Jay-Jay]

I had bad experience with white LEDs as rear parking lights. They made the rear parking lights look orange.
That's why I thought of searching for red LEDs... but now I'm confused. What should I buy?

... install some powerfull LED bulbs (without resistors or anything related to CAN bus Error free)
...

Great idea: if I buy T15 LEDs bulbs with no resistors, they absorb less than 16W, so they shouldn't reach the power limit of my BCM.
But i don't know what is the power limit of my BCM. It could be 10W, 8W,... who knows.
The only certain thing is that with 5W bulbs I have no problems, so I'd consider 5W as my BCM power limit.