Reverse signal for dashcam rear view

[Robert]

Or keep it handy and change your complete BCM coding from :
E0A4303A0A212031002009742E2B9C500F00708F60464DE0320400220800
to
E0A4303A0A212031002009642E2B9C500F00708F60464DE0320400220800

 

[Cb83]

Changed it now so will see how it goes in the morning when I reverse into my space at work, many thanks again @Robert

 

[Cb83]

Success thank you again @Robert

 

[Robert]

You are welcome .

 

[Frazthoms]

Sorry to add to an old thread but I’m connecting a rear dashcam to my 2019 T6 and trying to find the near side rear cable with the reverse light trigger. When engine is on and in park, all cables bar one (pin 4) are showing live. When I put into reverse the cable that was not showing live (pin4) remains not showing a live… in other words no difference when reverse in engaged.
there is a reverse camera already fitted by factory and I’m wondering if there some coding been done to alter the normal reverse light trigger on this cable that remains dead (pin 4).

the problem I have is I am handing off the van at the weekend to get boarded out so don’t have long to tap into this elusive cable.

can anyone help please.

here is a pic of the near side rear light block and cables I have (I don’t see a black/green cable)

thanks
Frazer

 

[Frazthoms]

I’ve since found the reverse trigger feed on the factory fit parking cam but it’s intermittently triggering the rear cam, probably too weak. I’m going to fit a relay with a proper 12v live and see.

 

[Cb83]

You may well find as I did that the signal is pulse width modulated, and some coding can rectify this, I'm sure a relay will do the same thing if you don't have access to vcds.

 

[david173]

I used a new 12v feed from the fusebox under the dash and used the reverse feed to trigger the relay to send this feed to power the camera.
I found because of the BCM in the car doing things to the signal (beyond my understanding) my relay played up, in the end i used a relay with a diode as recommended by another forum member which solved the problem. Might be worth getting that relay just incase. This one from memory :Halfords HEF560 Relay 12V 40A 4 PIN inc. diode | Halfords UK

 

[Frazthoms]

Thanks all.

I’ve ordered a relay with a resistor and hopefully it works but if not then at least I can pull off the tailgate panel to get to it and play. I’ve ran a ground and live feed into the tailgate so should eventually get there.

what was weird was I couldn’t find the references black/green cable and all the cables on the rear light block were live on ignition except one which was dead even with reverse engaged…

thanks again.

 

[Howzat]

You might want a relay that switches straight on but delays when the 12v reverse is cut for the following 2 reasons.
1. The pulse issue won't be an issue anymore so no coding required.
2. The reverse camera will stay active for XX seconds (is it 5?) like the rear sensors do.

Something like this 12V DC Delay adjustable timer relay which lets you set the delay from 0.1s to 25s.

 

[paddy26]

First thing I would do would be to check and make sure that Byte 11 Bit 4 is deactivated(unticked) in 09 BCM.

Thanks for this. It fixed the issue I had with my retrofit camera.

 

[Mehkor]

Or keep it handy and change your complete BCM coding from :
E0A4303A0A212031002009742E2B9C500F00708F60464DE0320400220800
to
E0A4303A0A212031002009642E2B9C500F00708F60464DE0320400220800

Hi Robert,
few years ago i did this coding to remove the relay but i just noticed i am not getting bulb fault errors. If there is a check mechanism for rear lights mine is not working . Did i code something wrong ?

Address 09: Cent. Elect. (J519) Labels:. 7E0-937-BCM-V1.clb
Part No SW: 7E0 937 090 HW: 7E0 937 090
Component: BCM PQ25 Max4 H80 0733
Revision: B9080001 Serial number: 0771 146151065
Coding: 62F279BA0A21209201280F746EEB8FD48FA0690F60CC6960320402A30800
Shop #: WSC 02739 790 12345
VCID: 68E78E899B1DCCC9E9-803C

 

[Robert]

Hi Robert,
few years ago i did this coding to remove the relay but i just noticed i am not getting bulb fault errors. If there is a check mechanism for rear lights mine is not working . Did i code something wrong ?

Address 09: Cent. Elect. (J519) Labels:. 7E0-937-BCM-V1.clb
Part No SW: 7E0 937 090 HW: 7E0 937 090
Component: BCM PQ25 Max4 H80 0733
Revision: B9080001 Serial number: 0771 146151065
Coding: 62F279BA0A21209201280F746EEB8FD48FA0690F60CC6960320402A30800
Shop #: WSC 02739 790 12345
VCID: 68E78E899B1DCCC9E9-803C

I can't remember now but some of the bits in the VCDS description for the BCM have reversed meaning.

Try to experiment with Byte 11 bit 6

Byte 11
View attachment 32550

 

[Mehkor]

I can't remember now but some of the bits in the VCDS description for the BCM have reversed meaning.

Try to experiment with Byte 11 bit 6

Thank you Robert,
So is diagnotics function only works for reverse light and plate lights ? Becouse my parking lights and brake light was not working i didn't tried to remove reverse light. just changed the bulbs and thought it didn't warned me becouse of coding i did.

 

[mmi]

Becouse my parking lights and brake light was not working

Perhaps you could try to flip the following to see if they make any difference for bulb warning

byte 19 bit 6 (from 0 to 1) - for tail light​

byte 19 bit 7 (from 0 to 1) - for brake light​