Sidelights not dimming (LED headlights)

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Bepis
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Sidelights not dimming (LED headlights)

Post by Bepis »

I recently added the ability to turn off my DRLs in the infotainment system using VCDS but have come across a strange bug I can't find documented anywhere else which has me stumped.

With DRLs enabled in the infotainment screen they do not dim when I move the light switch to side lights/parking lights. However, when I turn off DRLs my sidelights dim as they should.

Now on a Fabia NJ (MY16) I have access to which is also a PQ26 platform car with LED DRLs, it came with the infotainment option from the factory and the DRLs dim as they should when the side lights/parking lights are active regardless of the setting in the infotainment screen.

I'll post an auto scan in a short while.

The specific adaptation I changed was "(2) Daytime Running Lights "Tagfahrlicht Aktivierung durch BAP oder Bedienfolge moeglich" which I set to active.

Any ideas?
Bepis
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Posts: 321
Joined: Wed Jul 17, 2019 1:19 pm
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Location: Cheshire

Re: Sidelights not dimming (LED headlights)

Post by Bepis »

I've been messing around with the various light functions for the nearside/left side (UK passenger side) DRL and it seems that Dimming Direction CD2 is the side light/position light position on the light switch and when set to minimize rather than maximize the DRLs dim when the side lights/position lights are on. However, if I turn off DRLs in the infotainment screen it turns off the sidelights which is obviously quite bad. Although I only ever turn the DRLs off if I'm parked with my ignition on I'd rather it not be possible for me to accidentally be driving around with no lights at the front if I don't turn on the headlights.

I tried coding the light functions as they are on the Fabia I have access to but that broke various things and after reviewing the adaptation map the Fabias BCM is PQ26Hi4R H08 0087 whereas my Polo is PQ26 Hi4R H10 0094 despite being the same part number (6C0-937-089). The software also differed by a revision, the Fabias being revision C and the Polos revision D.

Setting dimming direction CD to minimize fixes my initial issue of the DRLs not dimming with the position lights turned on but introduces the issue of turning off the position lights if the DRLs are turned off in the infotainment. I did also figure out how to get the DRLs to dim when the indicators are on which is nice I guess.

My 11:30 pm brain is struggling so I'm going to leave it for now and put it back to how it originally was for tomorrow.

For reference are adaptation maps from the respective cars.

Fabia adap map for nearside (left side) DRL:
ENG124863-ENG115056-Leuchte2SL VLB22-Dimming_AB_2 100
ENG124863-ENG115060-Leuchte2SL VLB22-Dimming_CD_2 10
ENG124863-ENG115061-Leuchte2SL VLB22-Dimming_Direction_CD_2 minimize
ENG124863-ENG115065-Leuchte2SL VLB22-Dimming_Direction_EF_2 maximize
ENG124863-ENG115069-Leuchte2SL VLB22-Dimming_Direction_GH_2 maximize
ENG124863-ENG115064-Leuchte2SL VLB22-Dimming_EF_2 10
ENG124863-ENG115068-Leuchte2SL VLB22-Dimming_GH_2 0
ENG124863-ENG126577-Leuchte2SL VLB22-Fehlerort_mittleres_Byte_DTC-DFCC_2 4A
ENG124863-ENG115726-Leuchte2SL VLB22-Lampendefektbit_Position_2 48
ENG124863-ENG115057-Leuchte2SL VLB22-Light_Control_HD_AB_2 Always
ENG124863-ENG115054-Leuchte2SL VLB22-Light_Function_A_2 Daytime running lamps
ENG124863-ENG115055-Leuchte2SL VLB22-Light_Function_B_2 not active
ENG124863-ENG115058-Leuchte2SL VLB22-Light_Function_C_2 Blinken links aktiv
ENG124863-ENG115059-Leuchte2SL VLB22-Light_Function_D_2 not active
ENG124863-ENG115062-Leuchte2SL VLB22-Light_Function_E_2 Position lamps
ENG124863-ENG115063-Leuchte2SL VLB22-Light_Function_F_2 Parking light left
ENG124863-ENG115066-Leuchte2SL VLB22-Light_Function_G_2 not active
ENG124863-ENG115067-Leuchte2SL VLB22-Light_Function_H_2 not active
ENG124863-ENG115051-Leuchte2SL VLB22-Type_Of_Load_2 LED Tagfahrlichtmodul Signal

Polo adap map for nearside (left side) DRL:
ENG124863-ENG115056-Leuchte2SL VLB22-Dimming_AB_2 70
ENG124863-ENG115060-Leuchte2SL VLB22-Dimming_CD_2 30
ENG124863-ENG115061-Leuchte2SL VLB22-Dimming_Direction_CD_2 maximize
ENG124863-ENG115065-Leuchte2SL VLB22-Dimming_Direction_EF_2 minimize
ENG124863-ENG115069-Leuchte2SL VLB22-Dimming_Direction_GH_2 maximize
ENG124863-ENG115064-Leuchte2SL VLB22-Dimming_EF_2 30
ENG124863-ENG115068-Leuchte2SL VLB22-Dimming_GH_2 0
ENG124863-ENG126577-Leuchte2SL VLB22-Fehlerort_mittleres_Byte_DTC-DFCC_2 0
ENG124863-ENG115726-Leuchte2SL VLB22-Lampendefektbit_Position_2 0
ENG124863-ENG115057-Leuchte2SL VLB22-Light_Control_HD_AB_2 Always
ENG124863-ENG115054-Leuchte2SL VLB22-Light_Function_A_2 Daytime running lamps
ENG124863-ENG115055-Leuchte2SL VLB22-Light_Function_B_2 not active
ENG124863-ENG115058-Leuchte2SL VLB22-Light_Function_C_2 Position lamps
ENG124863-ENG115059-Leuchte2SL VLB22-Light_Function_D_2 Parking light left
ENG124863-ENG115062-Leuchte2SL VLB22-Light_Function_E_2 Nebellicht links
ENG124863-ENG115063-Leuchte2SL VLB22-Light_Function_F_2 not active
ENG124863-ENG115066-Leuchte2SL VLB22-Light_Function_G_2 not active
ENG124863-ENG115067-Leuchte2SL VLB22-Light_Function_H_2 not active
ENG124863-ENG115051-Leuchte2SL VLB22-Type_Of_Load_2 LED Tagfahrlichtmodul Signal
SRGTD
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Drives: 2020 AW Polo GTI+, Pure White.
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Re: Sidelights not dimming (LED headlights)

Post by SRGTD »

Sorry, I can’t help you with your coding issue, but I’m curious to know why you might want to have the ability to turn off your DRL’s.

I know when DRL’s were first made mandatory on new vehicles back in early 2011, it was possible to switch them off (my 2011 mk6 Golf GTD had that option in the vehicle settings). However, I think that option was removed from new cars a few years later; my 2016 Polo GTI didn’t have the option to switch them off.

From an insurance perspective, I wonder what an insurance company’s view would be if a car with the DRL’s turned off was involved in an accident, and the lack of illuminated DRL’s was held to be a contributory factor? Would that give the insurance company an excuse to reduce the amount of any claim payment?

Please don’t misconstrue this post as me being critical of what you’re trying to achieve because I’m not - I’m genuinely curious to understand why you might want to make this change. I also wouldn’t want to think a fellow forum member might suffer financially at the hands of their insurer with a reduced claim payment in the event of an accident.
Bepis
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Location: Cheshire

Re: Sidelights not dimming (LED headlights)

Post by Bepis »

Totally get what you mean and LED DRLs help massively with making cars a lot more obvious at a quick glance.

My only reason for wanting to be able to turn them off is for when I'm parked somewhere with my ignition on but my engine off so I don't dazzle other people in their cars at night in a services for example.

A few weeks back while waiting to pick someone up from the airport very early in the morning I was waiting in a nearby services and someone parked opposite me whose car had LED DRLs that were so bright I had to move.

I hadn't really thought of it before but my DRLs will light up my drive no problem at night so I was probably doing the same to them.

So the only reason is out of courtesy to other drivers.

People not using their lights properly is one of my biggest annoyances while driving. I've seen so many grey cars only appear 5 meters in front of me going down the motorway with no lights on whatsoever in heavy spray it no longer surprises me. Wipers on = lights on.
SRGTD
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Re: Sidelights not dimming (LED headlights)

Post by SRGTD »

Thanks for the explanation.
CarbonChaos
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Re: Sidelights not dimming (LED headlights)

Post by CarbonChaos »

There’s a simple solution to your problem I believe,code the DRL’s so they turn off with parking brake on
Bepis
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Re: Sidelights not dimming (LED headlights)

Post by Bepis »

I tried moving the position lights from function C to function F which had no effect.

I then switched dimming direction CD2 & 3 to minimize which did work but again left the issue of no position lights at the front if the DRL option was set to off and the light switch was set to position lights/sidelights. It also turned them off if the ignition was off whereas they would stay on by default.

However, while testing all of the lights this time with the engine running the car spat out 2 bulb errors, one for each DRL, and the module logged an open circuit fault for both although the DRLs were functioning.

So for how little I use just sidelights, I reverted the changes to dimming direction CD2 & 3 and will just have to live with the fact that it doesn't work as it should. The DRLs do still at least dim correctly if the front fogs are turned on and I can turn them off whenever I'm parked up.

The handbrake option did work but I was a bit weary of the handbrake switch ever failing on me and not having any DRLs until I could get access to VCDS.

Another thing to note is that even if I remove the option to turn on and off the DRLs in the infotainment screen the DRL behavior does not return to normal which is odd. If unchecked then removed, it re checks itself and disapears from the menu.

One benefit out of this whole exercise was that I got the DRLs to dim with their corresponding indicator which might help them be a bit more obvious to oncoming traffic.

For those interested:
Module 09 central electronics
security access: 31347
Adaptations:
ENG124863-ENG115063-Leuchte2SL VLB22-Light_Function_F_2 (left DRL)
Original: not active
New: blinken links aktiv

ENG124864-ENG115082-Leuchte3SL VRB36-Light_Function_F_3 (right DRL)
Original: not active
New: blinken rechts aktiv
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