Windscreen wipers not working

[26DIPP]

Happy Christmas,

 

My christmas present was my daughter coming home last night saying that the wipers stopped working.

This morning we checked fuses 26 and 44 and both are fine - swapped them for new ones.

So I guess that it is the motor... ?

 

How much hassle is it to change the motor? I have been in the bulk head before but not to do anything to the wiper motor.

 

[LGM]

Quite possibly, the wiper links are known to come off and only 1 side working. If both aren’t working and the fuses are fine there’s a good chance it’s the motor. 
If you’re in a rush for a complete wiper mechanism I’ve got one for sale. It’s Christmas and all so I’m not wanting an arm and a leg.

[UrbanPanzer]

Does not have to be the motor, the switch / stalk is before that and thats the bit that has human contact a lot in its life with some being far more violent than others.

 

imo you need to check there is power to the motor with the stalk in the ON position before condeming the motor.

[Breezy_Pete]

What year is the car?

There may well be a relay involved, within the onboard supply control unit. Bypass this with a cunningly applied festive paperclip to test motor. I'll hunt down a recent thread with pinout details.

Edited 25 December, 2021 by Wino

[KenONeill]

3 hours ago, 26DIPP said:

So I guess that it is the motor

Not necessarily; it could be the linkage seizing at the pivots.

[26DIPP]

Thanks for the replies at christmas.

It is a Fabia from 2009.

There is no action on any of the stalk settings.

I just had a look at the wiring diagram for the wiper control.

I will take the car into the garage tomorrow and start by checking power at the fuse - easiest. If there is no power, it has to be the switch. Otherwise I will check the motor. I could not see a relais. It sems to be controlled via the BCM - XS4 and XP4 outputs.

Edited 25 December, 2021 by 26DIPP

[Breezy_Pete]

(Dual) Relay is inside BCM. 

Short pins 3 and 4 of connector XP4 (with it still plugged in, just poke a conductor into the back of those two wire-entries).  Wipers should start going at normal speed and not stop until you remove this short.

 

Edited 25 December, 2021 by Wino

[Breezy_Pete]

See edit above for pinout info for shorting test. 

[26DIPP]

I did some measuring and had the motor out. The motor is running when connected directly to 12V in stage 1 and stage 2. There is no power from the supplying motor wire on the stage 1 or stage 2 contacts, i.e. probably nothing from the stalk, but could also be BCM. The earth on the socket has got continuity and there is a voltage on the run-on cable - XS4 -16.

I did not measure the stalk - stage 1 and 2 - outputs, but this is the most likely fault then.

So next will be steering wheel off.

[Breezy_Pete]

Do you have VCDS (Lite) and a suitable cable?

[Breezy_Pete]

This may be of some relevance, depending on how you get on with the stalk.  Removing plug from onboard power module - Skoda Fabia Mk II - BRISKODA

 

If you do have VCDS, you can probably observe the stalk inputs to the onboard supply control unit (Central electronics, module 09) in real time in measuring blocks rather than pulling the steering wheel off.

 

[26DIPP]

Actually VCDS is a good point for checking the stalk.

I had it connected to simply check for DTCs but did not think of output testing.

 

Googling for "relay" inside the BCM I got another link -

 - and I might just order this relay anyway.

[26DIPP]

Wino,

 

VCDS was a brilliant suggestion. I had homed in on the stalk, but the BCM registered all the positions of the stalk in the VCDS measuring blocks.

A relay / BCM is now ordered.

[UrbanPanzer]

Quite a few BCM's on ebay

[J.R.]

3 hours ago, 26DIPP said:

Wino,

 

VCDS was a brilliant suggestion. I had homed in on the stalk, but the BCM registered all the positions of the stalk in the VCDS measuring blocks.

A relay / BCM is now ordered.

Did you try actioning the wipers using "Output Tests" from VCDS?

 

It does sound like the BCM or relay if the motor worked when hardwired, if there is a seperate fuse for the wipers did you check it?

[26DIPP]

The wipers themselves did not work with VCDS because I guess they need the relay inside the BCM.

[Breezy_Pete]

Yep.

Are you changing the relay, or the whole unit?

 

Edited 30 December, 2021 by Wino

[26DIPP]

I ordered a used STG09 BCM. It arrived yesterday and I fitted it today. It was fiddly to fit.

I replaced a 6Q1 937 049 F with a 6Q2 937 049 F.

 

The wipers are working again, but I seem to have lost the cruise control. CC is coded via STG01 and when I try and recode it in Coding II the controller accepts it.

 

The other odd thing is, that the "new" BCM does not accept certain coding options - See attachments. The new one had a Shop #: WSC 00788 and coding 17420, while all other controllers have a shop#: 13765 and the old BCM coding was 25758 or 25788 - either worked and did not make a difference. The new one does not like the extra +08192 rear windshield wiper comfort function...

 

Also when I did the first scan I noticed that the gateway had changed to shop#: WCS00788.

I did manage after a few attempts to change the shop#: back to WSC13765.

 

So where have I gone wrong? Is the plug VS3 not in properly although they clicked nicely. Why does the new BCM not allow certain codings?

 

Old BCM

Log-TMBDC65J493165977-156770km-97412mi.txt

 

New BCM

Log-TMBDC65J493165977-156770km-97412mi_New CTRl09.txt

[Breezy_Pete]

@Tech1e would be the man to confirm, but I think the 6q2... versions are lower spec than the others.

Will you have a go at relay swap in the original?

[26DIPP]

Probably if I cannot fix it with VCDS. But not today as the car is driveable with windscreen wipers.

 

I forgot to say in the previous posting that the BCM came from a POLO 9N3.

Edited 31 December, 2021 by 26DIPP

[26DIPP]

Looking at this page - https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/2008-461/9/937-937050/ - are the units in the note column equivalent?

[Breezy_Pete]

At a guess, I'd say that it means, "this part number can be used to replace any of the following part numbers". I don't think the converse can be assumed.

 

[UrbanPanzer]

on the first module, it says "accepted the login", is it not supposed to say "coding accepted"  when re-coding.

Edited 31 December, 2021 by UrbanPanzer

[Breezy_Pete]

 I have a feeling this relay will substitute OK for the G8NW-2U that seems to be fitted in the suffix F modules: G8NW-2L-ASDC12 Omron Electronics | Mouser United Kingdom

The coil resistance is higher but that may not be an issue.

 

 

Did you say you'd ordered a spare relay @26DIPP, if so was it an exact part number match (I've seen such on ebay from China)?

Might buy a few anyway as there's something else I want to order from Mouser.

 

[26DIPP]

I have got one on the way from China.

The old one is desoldered and I will swap the BCMs when the iol one is complete again.

Getting another BCM was the quickest way of getting the car back on the road. It would have been nice if the "new" one had had the same spec.