UK-POLOS.NET - THE VW Polo Forum

Hello.

I've recently purchased a 2010 VW polo (6R ?) and it has a few issues with the electric windows, central locking and interior light. I found this forum and had a look at a few of the previous topics to see if it was a common problem and to look for solutions however, upon further investigation of the wiring by the fusebox there appeared to be a few dangling wires. I've undone the two torx screws holding the fuse box so i could get a better look at the back where it came from. It is solid red with white tracer that comes from fuse 23.

I had a look on the stickied fuse diagram and it said that it is the power to the following:
Selector lever -E313-
Rain sensor -G213-
Onboard supply control unit -J519- (T73b/39)
Engine control unit -J623-

My question is where does this wire go? It appears to have snapped off from a plug somewhere as i couldn't see any other wires hanging down that it could've connected to. I noticed it supplied the Onboard supply control unit which apparently does the horn and wipers, which aren't working either, which i only just noticed.

I've looked at where the Onboard supply control unit is located but i can't for the life of me get the lower dash panel off from under the steering column to access it. It appears that i'd have to take quite a bit of the dash out to get to the Onboard supply control unit.

If anyone could point me to a wiring diagram or even trace the wire in their own polo it'd be much appreciated. I'm pretty sure this will only fix the horn and wipers.

Many thanks.

The onboard supply control unit is also referred as the BCM.
But why don't you just re-connect the red wire to the fuse box? I guess that's the easiest way out.

iichel wrote: Mon Jul 31, 2023 8:47 pm The onboard supply control unit is also referred as the BCM.
But why don't you just re-connect the red wire to the fuse box? I guess that's the easiest way out.

Thank for the reply iichel.

The wire is connected to the fuse box already. The problem is i don't know where it goes, i just have this dangling wire connected to the back of the fuse box. ill see if i can upload a photo.

Here is a photo. Don't really know if it helps.

I think maybe i found where it goes but am unsure really as i am way out of my depth here. Please let me know if this is all just wrong.

I found the pin out for the BCM in another topic ( viewtopic.php?p=473516#p473516 ) and i think it is meant to supply the below pin in BCM. It is from terminal 30 in fuse box so i think it is likely:

Plug B - pin 39 - 0.5 wire - red / white colour - Input signal supply (30) for electronic

So far I have noticed i have no wipers, horn, central locking, electric windows or ability to open the boot so from what I've read on here the BCM controls all this. I guess ill just have to have a look tomorrow and see.

If anyone has a easy way of accessing the BCM without dismantling the whole dash i'd be very grateful as the lower dash panel seems to be glued on.

The best thing that could happen to you is that you find the other end of the red/white wire and splice/crimp them with each other correctly, ... since through the SB23 fuse electrical power is supplied to several important systems (some of which you have already mentioned).



On the 6R, the lower part of the dash is not removable.

Good luck finding that other end of the wire, you will need some contortion, a lot of patience and skill, to imagine and find that other end.
With the present length of the red and white wire, we're guessing you'll have to remove some cloth tape from the big wiring harness to locate the other end.Go


Good luck!! ... again ...

B111 is a connection that is buried inside the harness that was made by the harness manufacturer, ie it is not an accessible connection point.



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This is the second time I see this same circumstance in this forum. It is somewhat intriguing because it is not normal for that wire to break so cleanly inside a harness that it hardly has any abnormalities or movements.
Presumably someone who is on the side of the devil carried out such an outrage...

It is also to be assumed that that car was very cheap at the time you bought it... buying a car with all those malfunctions is not normal either.


https://www.youtube.com/watch?v=jYvcdhCbzJw

Thanks for all the info Ciclo.

So you'll be pleased to hear that it is fixed now and everything is fully functional. It wouldn't have been possible without the wealth of knowledge on this forum, so many thanks especially to iichel and Ciclo.

This evening i contorted myself upside-down under the dash to start investigating to look for the other end. I stripped back the cloth tape behind the Fuse box as far as i felt comfortably and it appears to be exactly as Ciclo mentioned, connection B111. Nowhere to found!!. At this point i had not received/seen Ciclo's second reply so was unaware that B111 existed and is buried in there somewhere. So without much luck so far i thought i'd just have a look at where it enters the BCM and temporarily spice it to see if that'd work.

So with much effort I removed the BCM and found the red and white wire and temporarily/permanently spliced into the connection. Plugged everything back in, and voila! it all works.

I was initially concerned with the splice as i noticed the original supply was much larger (1.0mm) than the BCM feed (0.5mm) and i would essentially be back feeding but assumed that if it was all originally rated at 5 amps then there shouldn't be an issue? as surely it is fused to the thinnest wire?

I have some suspicions that a previous owner may have tried fixing the problem as i can't see how the wire could be outside the rest of the harness and cloth tape. I think maybe they have re-taped the harness from the fuse box as it did appear different but TBH i don't know just glad it is all working.

As

ciclo wrote: Tue Aug 01, 2023 6:40 pm This is the second time I see this same circumstance in this forum. It is somewhat intriguing because it is not normal for that wire to break so cleanly inside a harness that it hardly has any abnormalities or movements.
Presumably someone who is on the side of the devil carried out such an outrage...

It is also to be assumed that that car was very cheap at the time you bought it... buying a car with all those malfunctions is not normal either.

.

I have some suspicions that a previous owner may have tried fixing the problem as i can't see how the wire could be outside the rest of the harness and cloth tape. I think maybe they have re-taped the harness from the fuse box as it did appear different. When i stripped the copper back it did look green but i cut another 30mm off and it was back to bright copper. So maybe corrosion? TBH i don't know just glad it is all working.

I did initially have a bit of buyers remorse as i knew the windows and locks didn't work but was pretty confident it was within my skills to fix the problem later as it didn't really affect driving, however, i failed to check if the wipers and horn worked which of course they didn't. So that was annoying. As you said, the car was indeed the cheapest i could find that wasn't a complete wreck or have 100s of thousands of miles on the clock. Now its fixed i feel much better about how much i paid.

Once again, thank you to Ciclo and iichel for the tremendous help, and thanks to this wonderful forum for being an invaluable resource. If any more challenges arise, I know where to turn for expert advice and support!

Luckily it was just a clean cut of that wire and you were able to do a 'By-pass'.

The thickness of the wires must be respected, although I can tell you that the 'original' automotive wire with a 0.5mm2 section where you joined the original automotive wire with a 1.0mm2 section will withstand the load for the systems it feeds.
Currently, wires with a section of 0.35mm2 are beginning to be used instead of the 0.5mm2 in older vehicles.

Thank you for the report!