Hi,  

Fabia 1.4 100bhp (BBZ) 2006, though I don't think that's relevant to this one.

 

My left hand indicator isn't working.  My local garage are 90% sure it's the bcm.  Does someone happen to know a part number for that please?

The hazards work fine, as do the right hand indicators and the main beam controls on the stalk.

 

A search found this thread linked below, that may be related, but no conclusion reached.  

 

Here are some videos from when I got back home from the garage and had a play around.  The indicators started intermittently working.  It almost looks like they come to life when the main beam flasher is activated but I don't think that's 100% consistent, though it does do that each time in the video below.

 

Stalk or bcm, or something else?  

 

https://youtu.be/v_fNfOefgvA
https://youtu.be/nRzqPoWX9lY
https://youtu.be/aS0mnltZ4HA
 

 

Edited 31 May, 20242 yr by jonmad

I'd think that you are correct to include the stalk assembly, a workshop with a suitable diagnostic tool could work out if the BCM O/Ps were following the I/P demands.

Must be on the input/stalk side of things, since the same IC within the BCM powers the indicators whether they are triggered by hazard switch or stalk.

Thanks both.  Yes, looking at the wiring diagram in the Haynes manual, attached, suggests whatever the input, it’s the same BCM output (16 as labelled). And odd that I got it to consistently come on with the main beam flash action, though as I say that tactic isn’t 100% reliable.

It's the stalk, replace it.

I had same issue replaced stalk job done.

Well, I sprayed a liberal amount of contact cleaner into the stalk and that seems to have done the trick!

Ah no, went out and tried it again, still intermittent/ only when also pulling the main beam flash, and then not every time. Let me see if I can get the wheel off, then it’ll be worth ordering a new stalk.

Just remember to mark your locking nut position on the steering wheel and be careful with the air bag lol.

Relax, the airbag can't go off without an electrical signal so if you disco the battery it's perfectly safe.

No airbag issues to worry about. But, this bolt should just undo, correct? With a 12mm spline socket on it. 

Yes of course, it's a normal R/H thread.

Thought so. Neither my breaker bar nor my impact driver are shifting it, and I was reluctant to try the latter 😞

Ok, is it a proper rattle gun or a Fisher Price looky-likey?

 

Also, are you trying to hold the wheel or letting the steering lock do its job?

 

Use a tube to extend the breaker bar and use maximum effort.

De Walt jobbie. But, cracked it - neighbour on the breaker bar, me holding the wheel 👍

And... stalk replaced with one off Ebay.  Indicator working again.  Thank you all.

Ahh, except, on a test drive it’s now behaving just as it was. Tested it about a dozen times on the driveway earlier as well. Grr.

Another video, just to show oddness.  Is this pointing to the BCM, seeing as the left indicator and the hazards are interacting in an odd way?

 

Made this little image just the other day for someone in the mk2 section. Your circuit board probably looks slightly different, but pretty sure the pins for inputs and outputs are the same.

If I were you I would focus on what the voltage is doing at pin 10 (LTS input) when indicating left, using stalk. Should be high (12V, I expect) when stalk is in neutral position.  Should go to 0V when indicating left.  LTS = left turn signal, RTS = right turn signal.

Hazards input will be on another pin, and seems to be confusing the issue a bit, by trying to operate simultaneously with stalk-controlled inputs.

 

 

Thank you @Breezy_Pete.  Just looking at your other post here (https://www.briskoda.net/forums/topic/440110-right-indicator-not-working-with-engine-running/?do=findComment&comment=4949991) on how to get at that, and the post above yours on how to conduct a voltage test with a multimeter.  I'll try and get a chance at the weekend to see if I can get to it to do some tests.

 

Back again

Post holidays, with the help of a friend we got at the BCM.  Looks clean enough.  Didn't try a voltmeter test as just unplugged it to check condition.  Sprayed it with contact cleaner and put it back together again.  It seems to be behaving itself slightly better, the indicators working consistently on a short drive.  Later, when I drove on the motorway I started getting a delay from pressing the stalk to the left indicator activating.  Back off the motorway and it started behaving itself again.  Needs a longer test drive.

 

Question - I've seen a few on eBay with different numbers where mine has 'S1S34' stamped it.  Does this have a known, specific meaning?  If I were to pick one up and swap it out, I assume getting one with the same numberings on it, including this 'S1S34', would be the best bet.  e.g. this one, https://www.ebay.co.uk/itm/185959278848 which also has 'II 1 38/06' where mine has 'I 2 13/06', suggesting a matching year ('06).  Would this still need coding? (using the code pulled off the current unit).  

 

Thanks

 

As far as I know, the only number that needs matching is the 6Q1937049D.

I doubt any of the others tell much/anything about the soft coding.

 

 

 

I Just put a multimeter on the inputs and outputs, left and right, with the engine off and engine running.

inputs:  for both left and right, the chosen input pin goes from approx +4-5V to 0V when the stalk is moved to indicate in that direction.

outputs:

- when the indicators are working, for both left and right, the output pin alternates between approx +10-11V and 0V as the indicators flash.

- however, when the left indicator does not flash, the LTS output pin does not alternate, despite the input still having dropped from 4-5V to 0V.

 

My simple deduction from this is that the input is behaving itself (and I've already changed the stalk) but I need to get and recode a new module.

 

 

And... now seemingly a successful result.  BCM from a VW Polo (same part number) arrived from eBay for the grand total of £17.  Fitted, recoded, dash back together (the headlight switch was tricky).  Result.

Thank you all, especially @Breezy_Pete for your help.  DM me and I'll buy you a beer.

Well done, no need for reward, but keep me in mind if you have any electric window trouble, or hear of anyone else needing repairs. 🙂