T6 OEM LED-headlight retrofit

[Robert]

Please read my 2 quotes below.
Check your voltages again and let us know your findings.

Okay, let's rock and roll.
I have worked out exactly the coding.
For the VW T6 LED headlights retrofit the following VCDS modifications have to be done in the long coding of 09 BCM/CEM

Byte 18 bit 0 1
Byte 18 bit 1 1
Byte 18 bit 2 0
Byte 18 bit 3 0
Byte 18 bit 4 1
Byte 18 bit 5 1
Byte 18 bit 6 1
Byte 18 bit 7 0
Byte 21 bit 0 1
Byte 22 bit 2 0
Byte 22 bit 4 1
Byte 23 bit 5 0

And by the way, all of the wiring from the halogen setup(either H4 or twin H7) can be reused for the LED lights except for the side lights.
Two new wires have to be run from BCM plug B
PIN5 to LHS lamp PIN10
PIN6 to RHS lamp PIN10
The reason is below.

View attachment 19044

This is the voltage produced by BCM to the LED headlamps on PIN10 when side lights are switched ON.
At the same time 12V DC is supplied to PIN12.

And when DRLs are switched ON both PIN10 & PIN12 receive 12V DC.

If there is only one PIN(either 10 or 12) supplied with 12V DC DRLs/sides will remain OFF. Obviously this should not happen when retrofit was carried out properly.

My DRLs with engine running.

Voltage at PIN 12.
View attachment 31855
And voltage at PIN 10
View attachment 31856

By the way, have you done any coding yet?

 

[scotia]

Please read my 2 quotes below.
Check your voltages again and let us know your findings.

all done,

when switch on side lights i have 11.5v on pin 10 and 12 LHS & RHS.

When engine running, 14.5v each

 

[Robert]

And what are your voltages with switch pointing at 0 (normally DRLs on)?

 

[scotia]

i only took one measurement earlier at position 0..pin 12 - 12v both sides.

i'll have to go back out to get pin 10

 

[scotia]

in position 0, pins 10 and 12 both sides both pins 12v

 

[Robert]

When switch is at 0 (DRLs ON) and engine is running your voltages at PIN 12 and PIN 10 should be approximately 14.7 V.

When switch is at (side lights ON) and engine is running your voltage at PIN 10 should be approximately 14.7 V and PIN 12 should be like that

which should give a reading of approximately 11 V on any ordinary volt meter.

Can you compare against your findings and advise?

 

[scotia]

When switch is at 0 (DRLs ON) and engine is running your voltages at PIN 12 and PIN 10 should be approximately 14.7 V.

When switch is at (side lights ON) and engine is running your voltage at PIN 10 should be approximately 14.7 V and PIN 12 should be like that

https://www.t6forum.com/attachments/20180214_222927-1-jpg.19044/

which should give a reading of approximately 11 V on any ordinary volt meter.

Can you compare against your findings and advise?

i'll look after dinner

 

[Robert]

Just FYI.

4G0907697G - power module for side light & DRL
7PP941571AE - power module for low beam & high beam

 

[scotia]

i'll look after dinner

ok, i have sth different..
(engine running in both cases)
Switch in position 0:
pin 10 14.6V
pin 12 14.6V

Switch in pos sidelights:
pin 10 14.5V
pin 12 14.6V

both RHS & LHS

what does that mean?!

my power modules are:
2x 7PP941571AE
2x 4G0907697G
"You could buy any pair of these
2 x 7PP941571AC or 7PP941571AE or 7PP941571A
2 x 4G0907697F or 4G0907697G”

 

[Robert]

Can you post the photo of your volt meter?
I just want to justify accuracy of your measurements.

 

[scotia]

It's a cheapo one - I didn't take pictures of the readings just wrote them down on paper..

it was on this setting:


im pretty sure thats not the image you wanted...

 

[Robert]

Can you confirm that PIN 7 was used as a reference GND point for all of your voltage measurements?

 

[scotia]

Can you confirm that PIN 7 was used as a reference GND point for all of your voltage measurements?

i used the battery negative, sorry didnt know to use pin 7..

 

[Robert]

So repeat all of your measurements.

EDIT:
You did say that your indicators work correctly so GND at PIN 7 should be okay.

 

[scotia]

ok i'll do that now.. oops..

 

[scotia]

yes indicators work.

engine off:

position 0
pin 10 11.9 11.9
pin 12 11.9 11.9

Side lights
pin 10 11.9 11.8
pin 12 11.8 11.8

engine on:

position 0
pin 10 14.7 14.7
pin 12 14.7 14.6

side light
pin 10 14.6 14.6
pin 12 14.6 14.6

 

[mmi]

1:
Pins number 8 and 13 on LED headlamp are empty/don't exist.

so it is pointless to run any wiring to them.

Interestingly on mine plugs have pin 8 wired on both Left and Right (as per wiring diagram). However, I haven't disconnected the plug to actually see if the respective pin in headlamp is empty as yours.

@scotia Does your headlamps have pin 8 occupied? I see that the plug is empty.

 

[scotia]

Interestingly on mine plugs have pin 8 wired on both Left and Right (as per wiring diagram). However, I haven't disconnected the plug to actually see if the respective pin in headlamp is empty as yours.

@scotia Does your headlamps have pin 8 occupied? I see that the plug is empty.

When i got my lights from vw 1st time, i looked at this and there wasnt at 8 or 13, i must admit with all the ball ache from vw to get a light that was in order i didnt check but i assume it to be the same - i dont see why it would change. I have a plug in 8 and 13.

 

[Pauly]

There is no pin 8 on the light units
This is a terminal 30 positive and in H4/H7 is used as the supply for levelling motors but redundant on led

 

[Robert]

yes indicators work.

engine off:

position 0
pin 10 11.9 11.9
pin 12 11.9 11.9

Side lights
pin 10 11.9 11.8
pin 12 11.8 11.8

engine on:

position 0
pin 10 14.7 14.7
pin 12 14.7 14.6

side light
pin 10 14.6 14.6
pin 12 14.6 14.6

Based on the info you have provided I would say that your both 4G0907697G modules are faulty.
I wish I was wrong.