Electric windows not working

[Hardcore5150]

Hi there, I know this subject has been covered so so many times but nobody seems to be saying what I am so I'm posting a new one looking for help.

 

Power windows stopped working on my Skoda fabia MK1 2005 months ago and finally getting fed up, I've replaced drivers motor and window switch already with no joy, the windows work for 10-15mins when I disconnect battery or connector to the motor, also works if I unlock the car with the key in the door yet doesn't work if I just unlock with the button on the key (odd as hell) I've also checked between the door and a frame all seems ok.

 

Looking some advance on what to check next as I've had a look at CCU etc but no visible issues and the fact it works when reset shows me the motors work fine aswell as the window guides etc, it just stops working after a short drive which means I have to reset it to put the windows up.

 

Ive read probably every forum I could find and have check anything I've been told to so this is the first time I've ever posted to forums. Appreciate any advice.

[Breezy_Pete]

Have you checked fuse 11?

[Hardcore5150]

Checked any fuses related to windows, not sure off the top of my head what fuse 11 feeds but if it's windows then yes mate, if it doesn't feed windows and feeds something else then no haven't checked. 

[Breezy_Pete]

It's an ignition 12V feed to the driver's side module, so relevant. On earlier mk1s it was only a feed to the wing mirror heaters I think, so people don't realise it's relevant to the later window motor modules.

 

Does your interior light come on when you open the drivers door? And do you get a 'lights left on' warning tone if you try to exit the car while they're still on?

 

 

[Hardcore5150]

Yes interior light comes on, and if I leave lights on and open the door it does the warning sound yes, going out to my car to check fuse 11 now but can't see it being an issue when they work fine when reset but who knows.

[Hardcore5150]

Fuse 11 in tact and blades look to be ok, this issue has has me scratching my head for months, I know an autospark will charge a tonne to diagnose and fix the issue so been determined to get to the bottom of it myself.

[Breezy_Pete]

Do you know for sure that the replacement module you fitted didn't have the same problem as your original?

[Hardcore5150]

That's what I've been worried about as there isn't really any way to tell as far as I know, I put it in and the windows worked fine (because it reset with battery being disconnected) so I left it thinking I had solved it then next day noticed it wasn't working due to the whole it only working for 10-15 mins after a power down and back up, it's very odd, the motors aren't the cheapest to keep trying them especially if I don't know if they all have this issue when sold second hand.

[Breezy_Pete]

I'm currently trying to work out the system by trying to figure out what every component on the circuit board is doing, but it's damn complicated. 

 

The 'key turned in lock' signal and the 'door open' microswitch signal from the door lock both go initially to the motor module, those signals are read by a microcontroller on the board, and then there's a bunch of circuitry that imitates the same signals for onward connection to the Central Convenience module and Onboard supply module respectively.

I've yet to figure out why they aren't just wired in parallel to all 'interested parties'. Hoping it will become clear when I've got the circuit all drawn out (don't hold your breath).

 

Drivers and passenger side module have a LIN data connection between each other (and no other modules), driver's side is the 'commander' and passenger side a 'responder' to use the politically correct terminology for master/slave, as seen in the datasheet of the responsible chips. 

 

Was your secondhand replacement exactly the same part number and also from a mk1 Fabia?

[Hardcore5150]

It is definitely complicated, surely it's been overcomplicated beyond just being able to direct current to the motor for up and down and then a safety limit should a hand be inside the frame etc but they have added all this other stuff for essentially no reason (give me a wind up window any day) 

 

Yes the replacement motor was from a fabia mk1 as far as I was told, but as you say it may have had the same issue when sold to me possibly (really hope not) 

 

Just hoping it's something stupid holding off the windows, even the window reset procedure of holding the key in the lock/unlock positions doesn't make the windows close or open as the manual would suggest and I'm not sure if this is also part of my issue or the manual is just plain wrong for my particular model.

 

[Hardcore5150]

I have been wondering if the passenger side motor would affect the driver's side considering drivers side is master, as I haven't replaced that side (that's if it even has a control circuit board like the drivers side has built into the motor) but as I say they both work when unlocked via key in the door its a very odd issue, I'm thankful I'm an AC engineer and not a car mechanic lol 

[Breezy_Pete]

It's partly down to over-zealous cost cutting I think. The pre-facelift had a different set-up with CAN bus connections to each module from the central CAN system, so there was a sort of supervisory presence, and I'm getting the impression they were more reliable. 

 

With the LIN system the door control modules only have each other and their inputs, with no central 'rebootability' if they get themselves in a muddle.

 

The passenger module has most of the same circuitry as the master, but even when its own side's switch is pressed, it sends that info across the car to the drivers side module, which then tells it to open its own window. Seems mad, but I expect there's some logical reason for it.

 

Must admit, I've never had any trouble winding windows up and down with a little handle, there's a weird snobbery about having 'electric everything' though.

 

When you get them going via key in door, do they (both) keep working for the duration of that journey? That could be a 'key' piece of info (apologies...).

[Hardcore5150]

They work for roughly 10-15mins totally fine up and down then at some point when I want the window up I find they don't work again, but again interrupting the power via battery or fuse or connector makes it work again but only for another 15ish minutes, so anytime I want to open or close my windows I've got to power them down and up or unlock the car with the key in the door (unsure why that works tbh but what you said earlier made sense of the microswitch almost resetting or activating them) 

[Hardcore5150]

I should note I had the multimeter out today and found voltages etc all ok, I did read across my travels that someone thought it was that capacitor on the control board on the motor that was what failed on them but unsure if this is true, I forget where I read it too as I've been on everything trying to solve this issue.

[Breezy_Pete]

At one point in my 'playing' with one of these off the car, I noticed that if you power them up with 12V just on the main thick wires that go to to pins 1 & 2 of the 8-way connector, the unit works, and consumes 20 or 30 mA of current when the motor is not active. After 10 mins this quiescent current drops to near zero and the thing no longer responds to the window switch input. 

If instead you also put 12V on the pin which fuse 11 feeds, it works and seems to continue to work for as long as that voltage is present (at pin 2 of the 6-way connector, the black/blue wire).  Is that one of the voltages you've checked at the module?

 

I think there are indeed other failure modes that seem to be within the module; some have reported success by changing the electrolytic cap, some also change the relay, which is trickier.  I've even tried changing out the main 'system' chip on a couple of boards; but so far the only unit that I've ever managed to resurrect was one I looked at years ago, where all I did was clean up the motor commutator and the connector pins.

 

There have been some slightly mysterious changes to the part numbers over the years since first used, so there's a possibility that there are design/component flaws that VW group have quietly fixed on newer units.  The reason I describe them as mysterious changes is that they appear in ETKA, and on the boxes of new parts, but aren't printed on the part number labels of the unit itself. They are a suffix of the form SK1/SK4 (on mk1 Fabia), different SK numbers on mk2 Fab, and different again on Roomsters. If you don't know exactly what car a 2nd hand unit came out of, I know of no way to find out which of these suffixes any given unit is. Polos and Transporters have suffixes starting VW instead of SK.  I have only guesses about what the suffixes mean, which I won't share now cos this post is too long already!

[Hardcore5150]

Yes check that voltage I did notice when not connected it drew 12volts for a split second then zero while holding the button, on the main pins from board to motor with motor detached, unsure if this is because it detects nothing drawing and stops the voltage but as I say when it's all connected up it works just not beyond 10 mins FS and sorry been in work all day so didn't get a chance to reply to you.

[xman]

Have you checked the door to pillar wiring looms? Pull back the rubber concertina bellows and check the wiring. Often at this age the wires have broken, due to brittle insulation and constant flexing. Start with the drivers door and work your way round. Need to check all doors. The connectors can also give trouble to due oxidation and corrosion, disconnect, inspect, clean reconnect.

 

Take time and care inspecting the wires as they can often be broken internally and the insulation intact, so they look ok, but the cores are broken.

 

Edited 14 July, 2021 by xman

[Hardcore5150]

I've checked drivers side only as from what I've been told/read the drivers side is the main control but maybe I should check passengers door etc then, just can't seem to figure out how it does work when reset but not any other time, to me doesn't sound like a wiring issue sounds more like a software issue or something, it's been very annoying to try to figure out.

[Breezy_Pete]

There are rumours of it being a software problem, but I can't see how it can be if it all used to work OK, now has limited function, but the software presumably hasn't changed. 

 

I can try changing capacitor and relay (and main system chip if you want) if you can post the circuit board across and be without it for a few days.  Minimal charge, no guarantee. 

 

[Hardcore5150]

It's just the fact it works when reset, to me that means wiring is fine as it does work it goes up and down, it just cuts out after 10 mins, using my work brain if it was an AC unit that works but stops after awhile I wouldn't be looking at a power issue (90% of the time anyway) usually it ends up being something unrelated to power, just have a feeling it's software or at the very least something wrong with the circuit board but could be wrong of course.

[LesCM19]

The control unit on my 2007 F1 packed up and am now using an identical s/h unit dated years earlier, 2005 I think. Just wondering how long it's got...

Edited 18 July, 2021 by LesCM19
I need a reason?

[Kelly_Heroes]

My front 2 windows are playing up both sides. You unplug the sockets on the drivers loom by the door and it works again most times or disconnecting the battery.

 

It was working fine for 2 weeks and now just stopped. The fuses are all good I will have to take the door card of driver side and have a look.

 

The control modules are these just on the motors or is there a separate main one for controlling both units as well?

[Breezy_Pete]

Earlier (pre mid-04, window modules with 6Q.... part numbers) cars had units that connected into the CAN bus so probably had a bit of control from more central stuff.

 

After that, the modules with part numbers starting 6Y... are more 'stand alone', or actually 'stand together' cos the only data connection they have is a one-wire LIN bus connection between just driver's and passenger side modules.

There are a couple of signal/status connections to other modules but no central control. My impression is that this makes them less reliable.

 

The wiring and connectors are different, so without considerable work you can't just fit the older style modules, sadly.

 

 

[Kelly_Heroes]

I unplugged the window motor and the windows work fine now.

 

I've cleaned and sprayed all the connectors as well. The circuit board inside the motor cleaned that as well as the motor coil to.

[Kelly_Heroes]

On 03/08/2021 at 21:58, Kelly_Heroes said:

I unplugged the window motor and the windows work fine now.

 

I've cleaned and sprayed all the connectors as well. The circuit board inside the motor cleaned that as well as the motor coil to.

This has lasted 3 days now and stopped working this morning.

 

I will this time just unplug the motor again and re plug back in. Then well see if the same thing happens again after 3 days.