Electric windows mind of their own

[aj_erst]

So the switches work, changed window motor drivers side, comfort unit, fuses, checked for wire brakeges in door jam etc. Tried resetting windows with key. Disconnected batter for a day to reset ecu. I'm convinced it's a software problem now, as sometimes the passenger window works then doesn't, some times both windows work fine then don't, sometimes you press the button to go up and the window goes down. I'm at a loss now and am hoping I've missed something, any suggestions? 

Edited 17 May, 2020 by aj_erst
Spelling

[TMB]

The drivers motor has the electronics inside that also control the passenger window. Perhaps the motor you fitted has faulty electronics if it wasn't a new one?

[aj_erst]

14 hours ago, TMB said:

The drivers motor has the electronics inside that also control the passenger window. Perhaps the motor you fitted has faulty electronics if it wasn't a new one?

Possibly, I will have to try a third one to rule that out 👍

[Fabia2312]

Hi I’m going through a similar nightmare with the windows.  Bought the car with windows not working.  The Drivers window did not function at all.  Passenger window would move in 1 inch steps.  Then the next time I got in the car neither window worked.

 

Disconnected battery, nothing, removed fuses and nothing.

 

Heard about the PCB faults on the board in the regulator (drivers window motor). Replaced the Relay and capacitor.  £10.00 Again nothing.
 

Bought secondhand Drivers side motor £48 after checking to get exact match for Software and hardware numbers.

 

Received new window motor, worked immediately Bingo!!  Then tested passenger window using both switches  drivers and passenger door - nothing.

 

Unplugged - replugged.  Turn ignition off on.  Then tried passenger window switch worked.

 

So now everything working perfectly.  Except turns out the motor I bought even though I bought from a UK seller for a UK car was back to front!! Presume from a LHD European car.

 

No worries, decided to use the Circuit Board from purchased Motor in my old Motor.

 

BUT - thought I would just try my original motor first.  It worked!!

 

Not convinced I left the door panel off.  Tried the windows next morning nothing!! 
 

Plugged in new motor, worked first time.  Passenger window did work but Not immediately takes a couple of goes.  Plugging in/out.  Ignition on/off etc. Doubt of permanent fix sinking in...

 

New motor has worked every time first time on the drivers window.

 

Swapped board off new motor with my original Motor.  Works perfect every time.  Passenger window worked BUT not with the Switch on the Drivers door.

 

Passenger door switch works perfect though.  Never mind pretty good result for now.

 

Left overnight - came back to car to try.  Back to square one - no windows working!!!!!

 

Ordered new switch £12ish aftermarket thing. Not got it yet.  Will clean original switch tomorrow and test.

 

In summary - every individual part has worked at some point .  All Switches, Wiring, Fuses, Motors with PCB boards etc...

 

The only thing that never worked was the original motor before I swapped out the relay and capacitor.

 

I think there is a Gremlin we are all missing.  But I’m at a loss at the moment.

 

Wiring seems solid, and swapping regulator (Drivers window motor) over seems to kick start something.

 

Have a feeling, two brand new window motors, two new door switches all genuine from Skoda and a new battery and everything would worked perfectly.  My Fabia is a 2007 and not worth the price of those parts so I will continue down the DIY route.

 

This is my first time joining a forum.  Many seem to go into huge detail like me but then don’t post a conclusion.  If anyone has fixed there window issue I would love to hear the last chapter!!

 

 

 

 

[Fabia2312]

Update - I think I understand a bit more now.

 

I’m still waiting for my new door switch.  I’ve cleaned  the old one, but that made no difference.  Each switch has four contacts.  2 for UP and 2 for down.  It only requires one contact to work. It’s a very simple PCB.  I think it could be faulty, I will confirm this once the new board has arrived and can then compare electrical values.  It’s not the actual contacts at fault though but likely a discrete component.

 

Turns out that it’s not swapping over the motor units that’s making the difference but just unplugging the main connector that’s doing it.  I was just not unplugging it for long enough before plugging it back in.  Swapping the motors just took me longer therefore a capacitor on the regulator must be holding some charge.  One minute should do the job.

 

The regulator (window motor) has 2 x power inputs.  A thick red/white 3mm Wire and a smaller one.  One of them is constant Battery power, the other is Ignition power.

I have noticed that my unit is getting ignition power even when the Key is out of the ignition. I.e when the windows are working, they still work without the ignition on.  This should not be the case, possibly taking me back to the wiring loom being at fault.

 

I have also noticed that once the window motor is Powered off, it is RESET and comes back to life for around 5mins.  Still need to time that to be sure.

 

This is consistent.  So I wonder if the constant ignition power is the root of the problem and then that is causing the  regulator to fail prematurely.

 

I only need the bigger connector plugged in to make everything work.  Not sure what the two wires In the smaller connector are for.

 

If anyone has managed to find a wiring diagram for that connector or knows more on what they do - that would save a lot of time.

 

And the search this Gremlin goes on!!

 

 

 

 

 

[Breezy_Pete]

Hi @Fabia2312, can you post a photo of the wiring you want details for?

I will certainly have a look at wiring diagrams; sounds like you are making interesting progress.

[Breezy_Pete]

The thin black/blue wire on pin 2 of a 6-way connector at the window regulator is powered from fuse 11, which in turn comes from the power rail known as 75x. This is described as:

"Switched-off positive behind relief relay of battery when starting (relay controlled through ignition/starter switch)"

 

In other words, it's the output of the x-contact relief relay, and as such it should be on at all times when ignition is on except when the key is in the cranking starter motor position, I think. This looks a failure of this relay. I think you'll find this in position 11 on the relay carrier behind the lower dash, driver's side.

[Tech1e]

Fabia electric window overview.pdf

[plo]

I chased my tail for weeks trying to figure out why the power windows were not working on my 2005 Fabia VRS. They worked intermittently. I replaced the relay on the PCB, however that made no difference.  I watched a few videos like this one...

 

https://youtu.be/lLTKYxBESP0

 

Thought I maybe had a faulty connection. Checked all wiring. No issues there. Checked the LIN wire from the drivers door motor (with a PICO scope) and found that the LIN wire didn't have a LIN signal when the windows were not working. 

 

Then I stumbled across this video..

 

https://m.youtube.com/watch?v=ZlExAJYp2x4

 

I didn't have a heat gun to try this. I was, however, certain that the motor (PCB) was faulty and needed to be replaced. TPS  wanted £169 ex vat for new motor . Local Skoda dealer offered a discounted price of £169 including VAT.

 

I decided to resolder the small chip with the QR code sticker on top, as I thought there could be a dry  joint between the chip contact pins and the board.Not easy to do...but figured it was worth a go. It worked. Windows have been fine now for 3 weeks.

 

I dont advise buying a used motor as it's pure luck if you get one with the correct software/coding. Also,  the coding / full part numbers are not shown on the motors. 

 

Warning.. obviously only attempt this if you are reasonable good with a soldering iron and were about to buy a new motor anyway. This is a last resort attempt at a fix. It worked for me.

 

 

 

 

 

Edited 23 May, 2020 by plo
Fix a typo

[Doily]

That's a great fix PLO!

 

But I feel sorry for the guy in the first vid.  He spent hours and hours (presumably paid for by the customer) swapping modules and mucking around with a 'scope and back probing, only to discover a broken wire by the door hinge.

 

He should join a Forum. Then he would learn like I have from the likes of TMB, Sep, Wino and many, many more that is the first place you look at. 

[Fabia2312]

Hi All

 

Thanks everyone for the help, wiring diagrams, advice and extra videos links that I had wouldn’t have found on my own.
 

It’s fixed now - but wanted to share my experiences just in case it helps anyone else.

 

I tried pretty much everything.  It’s shocking how many different things can fail on these windows. This is a pretty poor bit of engineering as their are so many different faults and fixes!!

 

I spoke with a very helpful senior Skoda technician.  It was clear that he had fixed many of these before but each one posed a different and time consuming conundrum.  Even with all his experience of this problem his best guess was faulty wiring in the door jams.  But it was not that.

 

I tried the door switch.  It was not that...

 

I changed the Relay on the Regulator Motor PCB, I changed the capacitor On the same board.  I reworked LIN Network Chip and the Other Large chip on the same board. Nothing....

 

I purchased a used motor with exactly the correct Year of manufacture, software and hardware version but it was from a LHD vehicle (DOH) and it was therefore the wrong way around and wouldn’t fit.  It worked!, the passenger window also came back to life.  BUT it stopped working after about 10 minutes.  I also  noticed - and I think this is important.  When the window motor was unplugged for a few minutes.  Plugged back in - everything worked for a few minutes until the board went into fault mode. IF during those few working minutes I turned off the ignition, the windows still worked.  This is wrong.

 

I then bought another used motor.  Plugged it in.  This time everything worked and stays working!!  Also when I turn off the ignition the windows don’t work - which is correct.

 

i also noticed during lockdown that the cars battery would flatten after a few days not weeks...

With the new Window Regulator (motor) this fault has also gone. 🙂

 

In summary - in my case - the fault was with the PCB board on the window regulator.  It seems to be something with the ignition power on the board.

 

It would be great to do some voltage comparisons on this board with my dead one and the third one I have, but I’ve lived without door panels for so long I’m trying to resist that.

 

There are two power lines.  Ignition Power (smaller wire) and Permanent power (big wire) The Lilac and white cable is the LIN communication wire, which tells the Passenger window to work.  These can all be tested quite easily, and can also with a loose wire be taken directly from the drivers to passenger window to check for broken wires.
 

Good luck if you have a need to read this...

 

 

[Breezy_Pete]

@Fabia2312 If you have a recurrence of trouble, please check whether there is (again) 'key not in ignition' power on that thin black/blue wire that I mentioned on 22nd May, which I believe is the one you are also referring to as the 'Ignition Power (smaller wire)' - please confirm.

It's not at all clear to me how something connected to this wire can make the x-relief relay stay 'on' when it should be off. If you do find this to be happening again, please consider replacing that relay. I'm not trying to say it can't happen, just that I don't understand it.

[plo]

Hi fabia2312

 

Glad you managed to get it fixed. I had the same issue with the windows still working after the ignition was switched off. Removing the old solder (with a solder suction pump) and resoldering the LIN chip resolved this. I took a couple of attempts at resoldering the chip to get it working.

 

Windows still working. Hope it lasts.

 

Been working on a fault with the central locking on the passenger door. Door would randomly lock and unlock when driving. Also noticed that a single press of the unluck button on the remote fob would unlock the drivers door then the passenger door too about 2 seconds later. Removed the window regulator carrier, reseated the plug on the door lock mechanism and it's been fine since.

 

Edited 7 June, 2020 by plo
Fix typo

[Breezy_Pete]

Just spotted something in the wiring diagrams that decreases my confusion a bit. The x-relief relay doesn't appear to work quite the way I thought.

In previous cars I've owned it tends to be hard-wired to the ignition switch, such that it's energised in ignition-on position, but not in the cranking starter motor position.

It doesn't seem to work this way in Fabias. It is energised directly from the ignition switch in the first click round position, but then not in either of the next two positions; ignition on and cranking. 

But...there's another connection to the relay coil from the Onboard Power Supply Control Unit; presumably this takes over control of the relay once the ignition switch is turned further. This opens up the possibility that the relief relay can be kept energised by that control unit, independently of the ignition key position/presence; whether by programmed function or fault condition.

 

I'll have to look into this some more