Strange (common?) central locking/electric windows problem

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Racehunter
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Strange (common?) central locking/electric windows problem

Post by Racehunter » Thu Nov 28, 2019 3:18 pm

My son has recently purchased his first car, a 2007 MY 1.4 Polo 5 door with low miles and full history. Its a really nice vehicle, and drives extremely well, so much so that it belies its age. Just one small mark to the rear N/S quarter panel for me to sort. Anyway, he decided that he 'needed' to have a replacement radio to allow for Apple Car Play, so purchased a head unit and that was added to my list of jobs!

Having left the car with me for completion of the work, he came back last weekend to collect it, only to find that there is a problem with central locking and electric window operation. It doesn't have remote C/L just 'key in slot' activation. All was well at the time the car was purchased, so this is something that has happened since then. I have no idea if the work I did has any bearing on this, but do actually doubt it as all I have done is remove and refit the N/S rear lamp cluster and remove OEM radio and fit a (cheap Chinese) double din item. I have obviously searched the forums for information and am amazed at how many VW vehicles have similar issues, but many different answers. The full symptom list from my fault appraisal is:

Only drivers door unlocks from that side with key, but interior light doesn’t come on.
• If all doors unlocked, only drivers door locks from drivers side with key and no alarm LED.
• All doors unlock from passenger side with key and interior light comes on
• All doors lock from passenger side, alarm LED on drivers side lock button flashes and interior light goes out.
• All doors lock and unlock using internal button on drivers door card
• Electric windows do not operate from drivers door switches
• Passenger electric window operates from passenger side switch


I have checked fuses and connections/wiring between drivers door and 'A' post and found nothing and checked connections behind the door card. This leaves me to think it might be either the door lock (is it a master to the system?) or the CCU, however with the weather the way it is I could really do with narrowing my fault search down even more, as the thought of stripping out the door on the drive is not currently appealing.

So, any ideas or alternate suggestions to help me sort this annoying problem?

Thanks

Steve

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Re: Strange (common?) central locking/electric windows problem

Post by RUM4MO » Thu Nov 28, 2019 4:33 pm

I'd guess initially from the "results" that the driver's door lock module is faulty as far as not unlocking any other doors and not switching the interior light on.

Electric windows could be either the driver's door switch panel or broken wiring at the door hinge area.

Edit:- probably being older and so kids are older, I convinced my daughter to "move on" her late 2009 Ibiza 1.4 16V SC this year and she replaced that with a new by pre reg SEAT Leon Cupra - hopefully her BF will take over looking after her car things soon!

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Re: Strange (common?) central locking/electric windows problem

Post by Racehunter » Thu Nov 28, 2019 8:27 pm

Not sure about the 'probably being older' This son is from my second time round family and didn't pass his test until later than most.........

Anyway, during a slight slackening of of the rain, off came the door card again and another good look at the cables and connectors. Now here is the strange thing. After removing both connector blocks from the electric window unit (drivers side) then clicking back in, the windows and central locking started working again. I then opened and closed the door (as in swing open) a number of times and the electrics returned to their 'less than perfect' functioning. Off came the connector blocks again and as soon as they clicked back into place, windows and doors worked correctly. This seems to be a cycle its now stuck in unfortunately so definitely not a permanent fix.

My thoughts are with a) a loose connector in the block (it seems to be the larger of the 2 blocks that affects the outcome), b) a problem with the board onto which the male connector terminals are attached to, or c) a fragile wire.

What I cannot work out is why the window winder motor should affect the central locking. If anyone can suggest why, I would appreciate it.

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Re: Strange (common?) central locking/electric windows problem

Post by Racehunter » Fri Nov 29, 2019 9:52 am

To assist this investigation, does anyone have any wiring diagrams applicable to this particular Polo. I did find a previous posting but the links to the diagrams no longer work.

Thanks in advance

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Re: Strange (common?) central locking/electric windows problem

Post by RUM4MO » Fri Nov 29, 2019 12:49 pm

Well that is progress, so either a permanent 12V or a permanent earth wire could be causing this, and it still sounds like it is due to breaking/broken wire(s) inside the conduit/boot that gets flexed when you open/close the door.

Have you tried squeezing this to detect any sharp/high points that would exist if a wire was broken/breaking? Also try pulling back into the door space or the void in front of the door (car body) to see if any wires are breaking/broken?

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Re: Strange (common?) central locking/electric windows problem

Post by Racehunter » Fri Nov 29, 2019 1:37 pm

Yes, I have had a good 'squeeze' of the conduit/moved cables back etc but could simulate the issue. To add to the 'symptoms', having left the car overnight, and having locked successfully all doors from the drivers door, I found the fault was back again, and the key only operated the mechanical unlock of the drivers door. So, this time it wasn't influenced by door opening. Stranger and stranger

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Re: Strange (common?) central locking/electric windows problem

Post by CarbonChaos » Sun Dec 01, 2019 9:24 pm

I will put my thoughts forward on this, this could be a connection issue in the door loom and/or pillar connection.
A good resistance check of the door loom wiring from the pilar connector to the door latch and window switch is a good next step ?

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Re: Strange (common?) central locking/electric windows problem

Post by Racehunter » Mon Dec 02, 2019 9:19 am

I was thinking of taking the door harness out to fully check it even though the pins (Male & Female) in the A post/door harness are all good and the actual harness within the rubber flexi is undamaged to fully check continuity between connectors/cables. I assume I have to take the inner door steel panel off?

Because the fault does not appear to be linked to opening and closing the door (After removing and refitting the main window power unit connector, I have opened and closed, locked and unlocked a number of times perfectly, then when left locked overnight, it reverts back to the fault) but is influenced by the plug/unplug process described previously and time, I wonder if it might be a circuit boar or component problem?

Can anyone explain the way the windows and central locking influence each other? I assume its through the CCU. Also still need a wiring diagram, so any pointers please. (UPDATE: I have door wiring diagrams now)

Thanks

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Re: Strange (common?) central locking/electric windows problem

Post by Racehunter » Thu Dec 05, 2019 4:51 pm

Well, the harness seems just fine with good continuity between connector pins, so I really think that this is to do with the PCB within the drivers door window motor unit. Possibly a capacitor, as this would explain the time related problem following a connect/disconnect sequence.

More investigation needed......

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