Facelift High Beam Failure

[ASRman]

Hi all,

Recently replaced my passenger side headlight after developing substantial water ingress after discovering a small crack in the lens. This previously led to the main beam, high beam and cornering lights all going out .

Installed the replacement headlight unit today (identical part number) which included the headlight unit, bulbs and all control modules. This was a used headlight bought off eBay and from 2017 S3 (exactly same as mine) .

Good news is that the main beam works now, as well as the cornering lights and LEDs. However the high beam is still out on that side. Quick scan on obdeleven shows an intermittent fault code stating 'supply for high beam'.

The seller on eBay has assured me this headlight worked perfectly on his car but is happy to refund me if needbe but I really don't want the hassle of returning it if it is a simple fix as otherwise the headlight was purchased for a great price and otherwise appears to be in perfect condition.

What are the possible causes for this? I am thinking potentially faulty control module?

TIA.

 

[DJAlix]

Water ingress can cause all kinds of issues with the main being corrosion. I would start by inspecting and cleaning all the contacts. As the head light has been changed I would then work backwards looking at the remaining components.

 

[ASRman]

Thanks buddy. I will ask my dealer to have a look at the contacts today.

Am I correct in assuming there are no seperate bulbs for the high beams? On previous cars it was just a separator that opens/closes.

 

[DJAlix]

Thanks buddy. I will ask my dealer to have a look at the contacts today.

Am I correct in assuming there are no seperate bulbs for the high beams? On previous cars it was just a separator that opens/closes.

That would have been for no-xenon I believe. Yours should be LED no?

 

[ASRman]

That would have been for no-xenon I believe. Yours should be LED no?

Mine are LED Xenon's (non matrix however). Think all new S3s come with Xenon's. That's interesting so it could be the bulb for the high beam that's bad also. Just adds to the mix of possibilities great!

 

[DJAlix]

Mine are LED Xenon's (non matrix however). Think all new S3s come with Xenon's. That's interesting so it could be the bulb for the high beam that's bad also. Just adds to the mix of possibilities great!

sorry new phone, that should have said bi-xenon. Being you have a 2017 FL S3 I would have thought that you would have full LED headlights (the level between adaptive bi-xenon and LED Matrix).

 

[ASRman]

sorry new phone, that should have said bi-xenon. Being you have a 2017 FL S3 I would have thought that you would have full LED headlights (the level between adaptive bi-xenon and LED Matrix).

No problem buddy thanks for the info. So assuming mine are full LEDs there will also be seperate bulbs for the high beam?

 

[DJAlix]

No problem buddy thanks for the info. So assuming mine are full LEDs there will also be seperate bulbs for the high beam?

Don't believe so.

Edit:

Actually I am a little surprised that you were able to swap your unit out and have almost evething working now that I have had time to think about it. That last few “more recent” vehicles I did this with needed the lighting unit to be “commissioned” via the online tool. This was for a Skoda Octavia and a VW Scirocco. VCDS does not pick any of this up so I would not expect a toy like OBDeleven to. Gonna need a trip to your dealership or someone like myself in order to confirm though as there is the “supply” error message present which points to a potential physical issue.

 

[ASRman]

Don't believe so.

Edit:

Actually I am a little surprised that you were able to swap your unit out and have almost evething working now that I have had time to think about it. That last few “more recent” vehicles I did this with needed the lighting unit to be “commissioned” via the online tool. This was for a Skoda Octavia and a VW Scirocco. VCDS does not pick any of this up so I would not expect a toy like OBDeleven to. Gonna need a trip to your dealership or someone like myself in order to confirm though as there is the “supply” error message present which points to a potential physical issue.

That is strange indeed. The headlight was installed at a dealer but they informed me no coding was necessary. The headlight supply error is a strange one also. Today I tried a basic settings of the headlights on obdeleven and both right and left headlights came back with the same supply error. I then acknowledged the basic settings and the fault has gone away but still high beam out on the left side. Dealer thinks it's the control modules so are replacing under warranty but I'm not convinced that'll fix it.

 

[Azzzhussain]

Did the control modules resolve the issue? I currently have the same situation and have been advised it is one of my modules even tho they’re brand new. The dealer who I purchased from showed a video of the headlight working but I can’t seem to find the issue

 

[Daimeon]

Any update?