Another Screen Washers thread

[ethrty]

Hi team, another one, and yes have searched!

I am a BMW wrecker, but we have a 2017 VW Transporter T6 FSI which we use as our parts van,
WV1ZZZ7HZGH061474
It is a brilliant van and I really enjoy driving it!

Having trouble with the windscreen washer not working when pull the stalk. It started intermittently not working and now nothing ever.

Manual tests:
- 12V not supplied to the pump by the van. have moved the wiring loom around etc and no change.
- Pump out of the car with the base submerged in a bucket and 12v applied, water will shoot out both pipes either side very strongly.
- Water lines blown out with compressor, water/bubbles/air come out easily and quickly so they are clear
- Pump in the car with water lines hooked up and power pump directly, the pump runs but no water comes out of jets.
- Fluid level is plenty (drained and refilled during diagnostic etc.
- Check Fuse 36 in center console and all good.

I can see the following live data on the Autel:
- BCM is seeing the stalk being pulled, which checks out since the wipers activate.
- Bonnet catch responds to open or closed correctly.
- component activation works for the wipers, and for the rear wash wipe, but does not have an activation for the front wash wipe - maybe this is a clue?
- no trouble codes stored on the vehicle

I think the next step is to trace the loom from the washer pump up and see where it goes to, perhaps someone already knows and could give me the pins to check continuity etc.

The only other issue I have with the van is the rear tailgate button no longer works.
Happened around the same time which is interesting, but I cant see why it would be related (the rear wash wipe works fine).
The latch works fine if i unlatch it using the Autel.

Thanks team!

 

[mmi]

the rear wash wipe works fine

T6 uses the same pump for front and rear window wash - the pump is driven either forwards or backwards to direct water to front or rear. This is done by reversing polarity of the pump feed.

Thus for front wash +12V gets into pump pin 1 and ground into pin2. For rear wash reversed - pin1 ground and pin 2 gets +12V.

As the rear wash works fine - pretty much proves that the wiring is good - but certainly would be good idea to verify neither of the pins at the pump is not shorted to ground (at stalk position "0").

12v applied, water will shoot out both pipes either side very strongly.

So you did try to run pump both ways?

As the voltage crossover is done in the stalk - suggests that the stalk is faulty.

T6 - Washers & Wipers Wiring Diagram

Wash/Wipe System Circuit Diagrams Includes front and rear screens, LED headlights washers and heated washer jets VIP Membership is required to download this document

www.t6forum.com

 

[ethrty]

T6 uses the same pump for front and rear window wash - the pump is driven either forwards or backwards to direct water to front or rear. This is done by reversing polarity of the pump feed.

Thus for front wash +12V gets into pump pin 1 and ground into pin2. For rear wash reversed - pin1 ground and pin 2 gets +12V.

As the rear wash works fine - pretty much proves that the wiring is good - but certainly would be good idea to verify neither of the pins at the pump is not shorted to ground (at stalk position "0").


So you did try to run pump both ways?

As the voltage crossover is done in the stalk - suggests that the stalk is faulty.

T6 - Washers & Wipers Wiring Diagram

Wash/Wipe System Circuit Diagrams Includes front and rear screens, LED headlights washers and heated washer jets VIP Membership is required to download this document

www.t6forum.com

This is Brilliant MMI, I only tested polarity across the pump in one direction.
When i did that, water came out both sides equally as strongly.
I will try polarity the other way on monday!

have ruled out the stalk, as the front wipers do activate as expected, but will take your advice!
The van has 320k on it so anything is possible at this point!