Question: DIY footwell lights with LED strip

[LMF]

Hi people

I am planning to buy a couple LED/SMD strips and use them as footwell lights by connecting them to the dome light wire which I should be able to find from behind the fuse box. I was wondering is this going to work? I believe this is the cheapest and easiest way to have a footwell lights.

Thanks

[mattaus]

Hi people

I am planning to buy a couple LED/SMD strips and use them as footwell lights by connecting them to the dome light wire which I should be able to find from behind the fuse box. I was wondering is this going to work? I believe this is the cheapest and easiest way to have a footwell lights.

Thanks

If you're wiring in parallel then it will work. You may have issues with the car reporting a blown bulb or something though given the increased resistance due to the new LEDs. That and unless you wire in a switch the lights will be on all the time.

Isn't there a bulb in the footwell already?

[LMF]

Thanks for the reply mattaus. That 'blown bulb' message could be a problem ... my comfortline doesn't come with the footwell light, I know I can do it properly with a footwell retrofit kit from overseas but it costs a lot more + the cost of coding which I don't think it worth the money for a couple of lights that only turns only when the door open.

Anyway I may give it a try and hopefully the 'blown bulb' message doesn't pops up

[DV52]

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Hi people

I am planning to buy a couple LED/SMD strips and use them as footwell lights by connecting them to the dome light wire which I should be able to find from behind the fuse box. I was wondering is this going to work? I believe this is the cheapest and easiest way to have a footwell lights.

Thanks

LMF: hi. Yours sounds like an interesting project and on any other car except one of VW's MQB platform vehicles, your approach would be entirely correct. However, VW appear to have made a number of radical changes in these cars, the least of which is their updated design philosophy for lamp protection. In previous models (for both VW and other manufacturers), the familiar fuse box was the source of power for each lamp. But in MQB vehicles, this no longer happens and the role of the Body Control Module (BCM) has been extended to both the provision of voltage/current for (most) lamps and associated fault monitoring. If you look at the fuse box designations on a MQB car, you won't find a myriad of fuse positions for individual lamps. Instead, the mk7 allocates 2 x adaptation channels (of the 19 x adaptation channels that manage each of the 35 x possible exterior lights) solely to the task of fault monitoring

What does this mean for you project? Well ... I think that it means that you will need to obtain the supply for your new LED lamps from the existing wires in the cabin loom (i.e. not from the fuse box). I've included a cut-down copy of the wiring diagram below that shows how the BCM (VW calls the BCM, "J519") and the footwell lights are connected (notice that a fuse is not involved in the ciruit)

As for OP's very good point about the likelihood of error messages (from the BCM in the case of a mk7) when it suddenly sees LEDs instead of the factory fitted incandescent lamps (I assume), I've included below a table showing how my LED footlights are programmed. I've only shown the critical adaptation channels for the footwell lights as the remaining channels in the Leuchte-set aren't active in my car. Alas, you will need access to a VCDS cable to change these channel settings.
Cheers and good luck with the project
Don

PS: I don't think that the setting for (6)-Leuchte30FR LC72-Dimmwert AB 30 in the table is critical. From memory, I recall that this value changes with the setting that the driver makes in the infotainment MENU screen - I think

[LMF]

WOW! ... Thanks a lot for the info DV52. Now I may need to think again

[LMF]

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LMF: hi. Yours sounds like an interesting project and on any other car except one of VW's MBQ platform vehicles, your approach would be entirely correct. However, VW appear to have made a number of radical changes in these cars, the least of which is their updated design philosophy for lamp protection. In previous models (for both VW and other manufacturers), the familiar fuse box was the source of power for each lamp. But in MQB vehicles, this no longer happens and the role of the Body Control Module (BCM) has been extended to both the provision of voltage/current for (most) lamps and associated fault monitoring. If you look at the fuse box designations on a MBQ car, you won't find a myriad of fuse positions for individual lamps. Instead, the mk7 allocates 2 x adaptation channels (of the 19 x adaptation channels that manage each of the 35 x possible exterior lights) solely to the task of fault monitoring

What does this mean for you project? Well ... I think that it means that you will need to obtain the supply for your new LED lamps from the existing wires in the cabin loom (i.e. not from the fuse box). I've included a cut-down copy of the wiring diagram below that shows how the BCM (VW calls the BCM, "J519") and the footwell lights are connected (notice that a fuse is not involved in the ciruit)

As for OP's very good point about the likelihood of error messages (from the BCM in the case of a mk7) when it suddenly sees LEDs instead of the factory fitted incandescent lamps (I assume), I've included below a table showing how my LED footlights are programmed. I've only shown the critical adaptation channels for the footwell lights as the remaining channels in the Leuchte-set aren't active in my car. Alas, you will need access to a VCDS cable to change these channel settings.
Cheers and good luck with the project
Don

PS: I don't think that the setting for (6)-Leuchte30FR LC72-Dimmwert AB 30 in the table is critical. From memory, I recall that this value changes with the setting that the driver makes in the infotainment MENU screen - I think

DV52: Does it means that I can't simply fit a fog light by connecting the wire to the existing rear fog light of my car?

[DV52]

DV52: Does it means that I can't simply fit a fog light by connecting the wire to the existing rear fog light of my car?

LMF: hi again. The fact that you have asked this question makes me believe that my first response was confusing. Please accept my apology for not being clearer.

The point that I failed to emphasise in my previous response was that I didn't think that you could take the supply wire for your LED footwells from a fuse position. But you could source this wire from any point in the existing footwell loom (inside the cabin). Also, if you want to change from an incandescent to an LED, then you may need to consider the possibility of error messages from the BCM (as suggested in mattaus's post) - but this really depends on the type of LED (i.e. how it is manufactured) and whether you leave the incandescent connected. If you do get errors, then my table may be of use

Same applies to the addition of a rear fog light. I have enclosed below my version of a wiring diagram for the rear fogs on a mk7 (showing the BCM connectors in this case), which I hope is of help.

As can be seen, VW simply connect the second rear fog in parallel with the original unit (which is what I suspect that you want to do as well). Notice also that there are no fuses in the circuit (like the footwell lamps). On the factory fit-out, the position of common coupling for the two lamps is a connector that is mounted on the rear lid, but it's probably easier to simply run a wire straight across the back lip of the tailgate as a retro-fit exercise. You also have two alternatives for fitting the new globe; you can either drill-out the blank part of the no-fog-light assembly, and force-fit (or glue-in) a new lamp holder, or you can buy an entirely new fitting that has the fog lamp base already installed. So no problems with the physical install.

The only other consideration is the programming side of the solution (i.e. will you be converting to LEDs and/or how is the Leuchte-set for your rear log light currently programmed). But this is not a difficult issue to resolve - just let me know what (if any) error messages you get and I'll try to help. If I don't have a solution, then I'm sure that other more experienced folk here will be able to find a fix! That's what forums like this are all about!

Cheers
Don