Fuse diagram

[GTI_PAPA]

Does anyone have a more comprehensive fuse diagram than the one provided in the owners manual? Or could someone direct me to the fuse that controls third brake light?

Cheers.

[h100vw]

Does anyone have a more comprehensive fuse diagram than the one provided in the owners manual? Or could someone direct me to the fuse that controls third brake light?

Cheers.

Probably connected to one of the other brake lights, shouldn't be a big deal to work it out, with the an assistant.

Gavin

[GTI_PAPA]

That's the problem. Manual only lists RHS and LHS exterior lights, no mention of third/high brake light or plain old tailgate lights. Might just have to remove and replace until I find the correct one.

Cheers.

[DV52]

That's the problem. Manual only lists RHS and LHS exterior lights, no mention of third/high brake light or plain old tailgate lights. Might just have to remove and replace until I find the correct one.

Cheers.

GTI PAPA: I don't mean to be a "smarty" - but why do you want to find the high-level brake light fuse? The reason why I ask is because the mk7 uses the Body Control Module (i.e. also known as the "On-board Supply Control Unit, 09 Cent. Electr., or sometimes CECM) to control all exterior lights.

This is probably too much information, but the BCM has the capability of controlling up to 35x separate lights, using what VW have termed "Leuchte Channels". In fact there are 665 such (adaptation) channels in the BCM of a mk7 devoted entirely to this activity. Sorry about this level of detail, but I find the way that the exterior lights are managed in a mk7 fascinating. I wrote a short paper on the topic which you can find on my VCDS reference thread. If you have trouble sleeping, I suggest that you start reading it -guaranteed to get you to sleep within 5 seconds!!

Anyway, back to your question - Unlike in older cars where the wiring for each of the lamps went back to an individual fuse, the mk 7 appears to fuse "banks of lights". For example, there is a single fuse for each of the two front headlight assemblies, rather than a separate fuse for each lamp in the headlight assembly. Protection (i.e. open circuit/short circuit) for the individual bulbs appears to managed by the BCM. This protection mechanism appears to be managed by the "(3)-Leuchte-Fehlerort mittleres Byte DTC-DFCC 4" adaptation channel in each of the 35 lights that I mentioned before.

To show you visually what I'm saying, I've provided for you (below) a copy of the bit of the wiring diagram for the "high level brake light" that is the subject of your post. The contents of the picture below is from VW's data.



In VW's wiring diagrams, the BCM is called J519. As you can see, there isn't a fuse in this circuit. Supply to the high level bulb is provided by the BCM which also provides power to each of the car's other exterior lights. The smarts in the BCM also seems to provide protection for the bulb (which would be the usual role of the fuse). M25 receives +12V from the BCM and it is earthed via circled 285 and circled 729 points.

So, are you having problems with this light? If so, can you describe the nature of the problem- please?

[GTI_PAPA]

The reason is because I am getting a "check third brake light" message on dash. Everything works ok, I've checked all brake and other lights for that matter. I'm a little old school, and from past experience and a lot of troubleshooting, I previously had an intermittent brake light issue, which was finally solved when it was discovered a fuse had blown and then re-fused. Swapping it out solved the problem. Based on what you've mentioned, it might not be as simple as that.

Cheers for the explanation.