A4 B7 dip beams come on with ignition only.

[liam walsh]

Hi All,

I've an A4 B7 2008 and dip beams , park lights and number plate lights come on with ignition only , the rotary light switch does not turn on or off the lights. The lights on the switch bezel come on as selected. The car does not have auto lights.
Main beams can only be activated by pulling back the dip/main beam stalk..
I got a known good OEM used replacement light switch but it did not fix the problem.
If I disconnect the light switch from the car the lights go off.
VCDS says implausible signal from E1 switch ( rotary switch for the lights)
If I pull fuse 14 ( steering control unit) the lights go off.
Internet searches show similar issues on other B6/B7s but I couldn't find any useful solutions.
Anyone got any experience of my issue or a next logical step for trouble shooting this

TIA.

[Crasher]

The dipped beams should only come on with the ignition on but the sides/number plate lights should come on ignition off but you should be able to turn them off, obviously UNLESS someone has been playing with the BCM soft coding. History and full VCDS scan (with VIN)?

[liam walsh]

Hi vin is wauzzz8E8A140944. Only 1 fault code on vcds 1 Faults Found
01800 -Light Switch (E1)
27-00 implausible signal.

I had a similar but intermittent problem about a year ago and replaced the switch E1 with a VEMO switch and I thought fixed the problem but the issue still appeared very intermittently and very infrequently . Then it stopped working completely and I replaced with an OEM but used switch. Nil fix. I could buy another VEMO switch just to see.

[Crasher]

Vemo parts have always been good in my experience, but that VIN doesn't work.

[liam walsh]

Wauzzz 8E 2 8A140944 sorry I missed little 2 didn't think it was important.

[Crasher]

OE switch 8E0 941 531 C 5PR (5PR just means black) which is £164.40 genuine and a Vemo V10-73-0266

https://digital-assets.tecalliance.services/images/3200/a48fded0f9984a7454b4480f3d279956a6edf8e8.jpg?ver=3 .99.0.b0c4c5bb8e

[liam walsh]

Thanks for looking to that for me .
The new to me used OEM switch I have is p/n 8E0 941 531 A 5PR would the A make a difference? I was thinking A and C were just revisions but essentially the same parts?

[Crasher]

8E0 941 531 A 5PR (obsolete genuine) is for cars 08/04>01/05, 8E0 941 531 C 5PR is for cars 01/05 to 06/08 and yours is 04/02/2008.

[liam walsh]

Crasher thank you very much for taking the time . . You've been very helpful. . Metzger switch ordered as stock of the right VEMO switch seems to be non existent in Ireland at present.. hopefully that fixes my issue. I'll report back in any case.

[liam walsh]

New switch installed, nil fix. More head scratching to be done .

[Crasher]

If you fitted a Metzger 0916734 you are looking at a BCM J519 problem.

https://digital-assets.tecalliance.services/images/3200/d3b5bfa11172edc98958a94b931b89e32b4eae08.jpg?ver=3 .100.0.1546dd6ccb

[liam walsh]

Yes a 0916734 metzger fitted, for info it feels more OEM that the VEMO but that's besides the point.
I might try checking continuity of the wires from the bcm to the switch before looking at a new used bcm, is coding in a used BCM difficult with VCDS? I have elsawin diagrams to identify the wires for con checks.

[Crasher]

The BCM is specific to the car, a Vehicle Intelligent Part but I think it is too early for component protection.

[liam walsh]

Saga continues ,

I replaced BCM J519 with a used BCM 8E0907279L ( my original was 8E0907279N but ETK shows as alternate ) . I checked coding on VCDS and both BCMs have the same coding..
Nil fix . Still getting E1 implausible signal but with the new BCM Switch E1 can now turn on and off the lights but turning on park lights turns on dins aswell. No other function works , still no full beams unless lever pulled back and no front or rear fogs.

So because i had it there i fitted the E1 switch that is not correct for the car per ETK p/n 8E0 941 531 A 5PR and with that installed full beams work as normal , fogslight front and rear work as normal but it doesn't turn off the lights , they can only turn off with ignition off. Also I noticed this particular switch p/n 8E0 941 531 A 5PR only does this with the new used BCM i fitted .

I'm not sure what to do next , what other module could be causing this or possibly wiring? 🤔

[Crasher]

The turn signal/dipped main switch or steering column controller.

[liam walsh]

The turn signal/dipped main switch or steering column controller.

Cheers Crasher. I'll keep at it.

[pdlh]

Just a thought, in the VCDS module, Central Electronics is there any way your car has been coded as 0xxx2 (Northern Countries) where I believe it’s law for their lights to be on all the time, (remember old Volvo cars from back in the 80’s 90’s when you used to see their lights on all the time). Any chance you car is coded so the lights come on as soon as you turn on the ignition because it thinks it’s from Scandinavia?

0?xxx: Light Sensor
0 = Light Sensor not installed
1 = Light Sensor installed
0x?xx: Trailer Hitch
0 = Trailer Hitch not installed
1 = Trailer Hitch installed
0xx?x: Headlights
0 = Halogen Headlights
1 = Xenon Headlights
0xxx?: Country
1 = Rest of World
2 = Northern Countries (Finland, Sweden, Norway, Denmark)
3 = USA
4 = Canada