Right Indicator not working with engine running

[Purbeckfossil]

Hi, The right indicator on my daughter's Fabia (2005) has stopped working when the engine is running. When the engine is off, all indicators work when the hazard switch is ON. When the ignition is ON, both indicators work. When the engine is running, the right indicator does not work. This is the second time it has happened. On the previous occasion, I first replaced the hazard switch, then the stalk assembly. I talked to our local garage repair guy and he thought it would be the hazard switch and persuaded me to buy a genuine VW part. It still didn't work. During the summer, it suddenly started working OK. My garage guy asked if the car was left unused for any period of time. My daughter is a ski instructor so the car does stay in the snow for up to a week without use during the winter.  He thought it may have been condensation in the wiring, and it had dried out during the summer. Now it's October and it's non-working but the car is driven regularly. Anybody had this type of problem? I have tried a hot air gun on low and taken the vent out on the centre-dash where the hazard is but no luck so far. Should I try an electrical switch spray? Any other suggestions welcomed, Cheers

[LightRain]

I would agree it is more likely wiring than component issues, I'm unsure why they would have suggested components before checking the wiring.

So, right flasher on either side is misbehaving with the engine running, idle and under load and driving conditions? You have new hazard and stalk and both are OEM?

Do you hear the flasher unit ticking when the right flasher isn't working, what about the dash indicator light, or is it all completely dead on that side?

 

I can't think of what it could be right now, vibration is a concern, also some dirty signal to the power control unit while the engine is on.

Anyway, checking voltages and voltage drops at key points is as good a place as any to start. Do you have a multimeter, failing that a test light? Go backwards from the easiest accessed indicator. Test the supply line. With the indicator on and ignition on it should read a fluctuating 12 V (test light flashing strongly), with the engine on it will probably read 0 V (test light off), but there may be a hint of voltage (test light flashing very dimly). Basically you are looking for where (if anywhere) the signal is always present.

[Breezy_Pete]

Will have a look at current flow diagrams later, but for what it's worth, the indicators are fed from the on-board supply control unit; driven by a solid state device. The ticking noise is from a piezo tweeter in the instruments module (cluster).

 

The main difference between engine running and ignition on (or off) is system voltage. Engine running it's nearly 2V higher, so could be a marginal wiring short that's only conducting enough to shut down that channel of the solid state device at this higher voltage?

[LightRain]

14 minutes ago, Wino said:

The ticking noise is from a piezo tweeter in the instruments module (cluster).

Yeah, the diagram shows this. Makes me wonder why they suggested replacing the hazard switch as that just switches one pin on the power control unit.

 

I'm still not entirely sure if this is just a hazard thing or when indicating too? If it is just a hazard thing, that's a little odd.

[TMB]

Have you checked the contacts on the indicator bulb holder and headlight? The bulb holder isn't hard wired, it relies on some contacts when you twist the bulb holder in. They can become intermittent if they're not clean and making good contact.

 

Edited 25 October, 2017 by TMB

[Purbeckfossil]

Thanks for all your comments. In answer to your Q, Light Rain, I don't hear the flasher indicator unit ticking, AND the dash indicator light is not ON either when the engine is running.  - nAlthough I have a multi-meter, I'm not great on electrical diagnosis and would need an A-Z mugs guide to work through.

I did have another chat with my garage guy and he said it might be a faulty Body Control Module (BCM) but would have to schedule an auto-electrician to diagnose further (sounds like a few hundred quid if we go down that route). My Fabia Haynes Manual doesn't even have any reference to a BCM or show where it's located, but youtube shows it behind the fuse box. Is it worth getting an ebay BCM second hand and taking a chance? AND, if so, does it have to be re-programmed on the car ECU? (I can't believe how useless Haynes have become since I had my classics in the 70's & 80's)

 

Cheers

[LightRain]

I'd advise against buying a part until you know, without any doubt, it is faulty. This applies especially for an expensive one. This applies even moreso for something that is working under some circumstances.

 

As Wino says, the onboard power control unit does all the work regarding flashers. Generally what happens:

1. You send a signal via the stalk (or hazard switch) to this unit.
2. It then intermittently powers the indicator lamps and sends a CAN bus (the car's internal computer network) signal to the instruments to flash the light and make the click.

The same CAN bus lines are used to communicate both left and right flasher command (as well as numerous other things) to the instrument panel. So it is quite safe to assume the connection between control unit and instruments is good. It is also safe to assume your stalk is operating fine as it is new.

 

I have never worked on this particular vehicle so I can only go by diagrams and what my intuition would tell me. I also can't give you specifics on locations, although this control unit is likely under the dash, as you noted, near the fuses somewhere. It will be bigish, black, have several connectors going into it. The CAN bus lines and stalk commanded flasher uses connector XS6 (16 pins) and the hazard switch uses connector XS1 (6 pins).

 

Connector pins for XS6:

• Left stalk input: pin 10
• Left output: pin 16
• Right stalk input: pin 12
• Right output: pin 14

And for XS1:

• Hazard input: pin 6
• Hazard indication light: pin 3
• Same XS6 output pins for left and right

I think I would proceed by checking the signals going into and out of the onboard power control unit both with and without the engine running and both sides. Comparing left vs. right and running vs. not running. A multimeter test is good enough for this as of now, after all you are just establishing if anything is happening when you make a flasher command. You would do this with the multimeter in DC voltage mode (20V would be typical). You would then carefully insert a probe into the back of the relevant pin on the relevant connector and ground the other probe to the chassis (or nearby ground point).

 

Don't be too harsh on Haynes, there is so much complexity and specialist equipment used in diagnosis these days they really can't do much. Although, isn't there even a mention of the various computers in the wiring diagram section?

[Breezy_Pete]

Onboard supply control unit is the same thing as what your garage guy is calling the BCM.

It's just above the accelerator pedal. If you take off the lower dash covering (see this how-to, the first few steps show removal of this panel nicely), you'll see it with all its connectors hanging down.

 

 

[Purbeckfossil]

Wow! Thanks for all this info. I was just about to start getting the multi-meter in the toolbox when my daughter rang to give me some more feedback that may suggest the issue is more mechanical than electrical.

 

So, she has found that if she turns the steering wheel to the left and then indicates right (with the engine running) it works. Then as she turns the wheel to the right the indicator stops!!! She has repeated this more than a few times.

 

Question: Is there some electrical contact on the wheel that needs to be checked? Full marks to her for trying something left field.

[LightRain]

As far as I can see there shouldn't be any connection between wheel and indicators. However there is probably a lot of wiring around the stalk that is in close proximity to the wheel. There could be something that is being stressed when turning, a misplaced wire being pulled taut or something. This would fit with problems on input to the onboard power control unit.

 

Depending on ease of access, you can still meter the relevant inputs to the onboard power control unit, to see what happens when you turn the wheel. This would confirm the circuit segment that is causing the problem. Although the wheel action seems to point to control side, there is a lot to be said for a belt and braces approach.

[Purbeckfossil]

Hi LightRain, I have replaced original unit in the car. Interestingly, with ignition ON and car NOT RUNNING both indicators work!

 

On XS6,  ignition ON and car NOT RUNNING - Voltage on left output (pin 16) and right output (pin 14) is about 11.85v.

 

With car RUNNING, voltage on pin 16 (LEFT) is 14.2v and ZERO on pin 14 (RIGHT). Left indicator working, right NOT working.

 

Does this indicate a faulty ECU? / Where do I go from here?

 

If so,there are a few on eBay with the same part numbers but come from different cars i.e. 1.9 Fabia TDI, Seat Ibiza 1.2 (our engine size), 9N3 polo, 2006 Polo 1.2

 

Cheers Paul

[KenONeill]

@Purbeckfossil - I presume the parking lights (activate be setting indicator switch with engine running, then switch off) work correctly? Do the hazard lights work correctly?

[Breezy_Pete]

I don't have any time this evening but hope to revisit this tomorrow with a spare unit to hand.

[Breezy_Pete]

With everything switched off try unplugging XS6 and measuring resistance to chassis of each of the loom plug sockets of pin 14 and 16. This may tell us if there's a fault outside the unit.

Expect quite low Ohms on each as you'll be measuring cold resistance of all 3 bulbs on eac side in parallel. They should read about the same.

[Purbeckfossil]

Hi Ken, can confirm that all parking lights are working and hazard lights also with engine on and off.

[LightRain]

On 18/01/2019 at 17:36, Purbeckfossil said:

Hi LightRain, I have replaced original unit in the car. Interestingly, with ignition ON and car NOT RUNNING both indicators work!

 

On XS6,  ignition ON and car NOT RUNNING - Voltage on left output (pin 16) and right output (pin 14) is about 11.85v.

 

With car RUNNING, voltage on pin 16 (LEFT) is 14.2v and ZERO on pin 14 (RIGHT). Left indicator working, right NOT working.

 

Does this indicate a faulty ECU? / Where do I go from here?

 

If so,there are a few on eBay with the same part numbers but come from different cars i.e. 1.9 Fabia TDI, Seat Ibiza 1.2 (our engine size), 9N3 polo, 2006 Polo 1.2

 

Cheers Paul

 

I don't have access to my documents at the moment.

 

I think that there should be battery voltage at pins 16 and 14 when the left and right (respectively) indicator are desired, and both when hazard is on. From what you have said, it sounds like either your desire for right indicator is not getting to the unit, or the unit isn't sending the signal to the lights.

 

If hazards work in all conditions when they are expected to, then I would heavily advise against concluding the control module is broken.

 

For some additional homework, can you measure terminals 10 and 12 with the XS6 plug connected? These are the control lines for the indicators through the stalk. With no indicator desired, I think they should always be at battery voltage whenever the indicator would be available. When indication is selected pin 10 (left) and 12 (right) should go to 0 volts.

 

Take care.

[Breezy_Pete]

I agree with @LightRain's analysis, finding pin 12 not going to 0V when the stalk is moved to the right would confirm a dodgy connection or wire on the input side of things.

[Purbeckfossil]

On 18/01/2019 at 17:34, Wino said:

With everything switched off try unplugging XS6 and measuring resistance to chassis of each of the loom plug sockets of pin 14 and 16. This may tell us if there's a fault outside the unit.

Expect quite low Ohms on each as you'll be measuring cold resistance of all 3 bulbs on eac side in parallel. They should read about the same.

 

Further feedback as requested.

 

Ohms - XS6 unplugged, Pin 14 1.2, Pin 16 1.2

 

Voltage XS6 - Pins 10,12

 

Pin 12 Ignition ON, Not Running, Right Indicator ON = 0v

Pin 12 Ignition ON, Car Running, Right Indicator ON = 0v

Pin 10 Ignition ON, Not Running, Left Indicator ON = 0v

Pin 10 Ignition ON, Car Running, Left Indicator ON = 0v

 

Regards

 

 

 

 

[Breezy_Pete]

Presumably the right indicators were in non-working mode at the time of those measurements, and the connector plugged back in for the voltage measurements?

 

If so that points the finger of suspicion back towards the control unit.  I'll just pop into your other thread and have a look at the link that KeithCheetham invited me to peruse.

I've just taken a photo or two of the chip inside the control unit which 'does' the indicators, and it isn't straightforward to replace; but if available to buy, I'd happily give it a go.

Back in a minute.

 

Wonder if @Tech1e can offer any guidance on coding these units, from his vast experience?

Edited 20 January, 2019 by Wino

[Breezy_Pete]

This is the little fella:

 

 

Looks to be obsolete from the usual sources, but ebay has a fair smattering of them at various prices.

 

I'd still be tempted to try A.N. Other unit with identical part number from a car as similar as possible to yours ahead of the 'surgical' approach, but if you could be without the unit for a few days, it could be a plan that would avoid any coding issues if it worked.

What is the exact part number of the unit you have?

Edited 20 January, 2019 by Wino

[Purbeckfossil]

You chaps are truly very helpful, Thanks. I did think that zero volts on pin 14 when running & right indicator ON seemed to suggest a BCM fault, (in my non-electrical humble mode) assuming their is only one wire to the indicators.

 

I am quite prepared to get an eBay unit and give it a try if you think that is the likely culprit. (I am quite happy to donate the old unit FOC to anyone that wants some soldering practice)  (It's still way more cost effective than the £500 option) My friend has had a few Passats and has the VCDS stuff, so between us, we should be able to get it sorted.

 

If I do get a unit, is the sequence to use VCDS to take a map of the old unit, then re-programme the new one when in situ - assuming the right indicator show willingness when plugged into the replacement BCM?

[Breezy_Pete]

I think the VCDS stuff is as simple as reading (with a VCDS scan) the existing coding of the unit and its sub-unit which is the 'gateway' and then - as you say - putting the new unit in the car and altering the coding (as necessary) of those two to be the same as what they were in the original unit.

Here are examples of the coding on our car, do you have an existing scan you could look at? Likely to be different codes.

 

 

I'm having some doubts about the chip transplant working anyway, because of what you've said way above about the dash not even thinking the indicators are working when they aren't. That suggests the driver chip isn't even being told to switch on the right indicators, for whatever reason. 

[Tech1e]

There are three different types of central electrics modules (also known as Boardnetz), technically not a BCM. 

 

6Q0 and 6Q1, these are interchangeable and will work on any MK1 Fabia. 

 

6Q2 is a lowline unit and won’t operate things like cruise, electric mirrors and a few other things. 

 

The five digit code code code from the old one will be enough to get most stuff working the same. There are a few adaptions you can set. Getting a module from a post 05MY car (if memory serves) will get you the three flash comfort indicators (lane change).

[Purbeckfossil]

Thanks x3. 

 

Will get one off eBay. Will report back in about a week

[TMB]

I wonder if it would be possible to rewire the indicators using on old school flasher unit. I suspect it may be possible. If this happened to mine it might be something I'd consider.