Hi all,

My 2009 Roomster's driver's side window has become conscious (!) and is going up and down by itself and I can't quite figure out why. The fault is intermittent.

I've tried recalibrating the fully open and close points (by clicking three times or holding on for a few secs) but that doesn't seem to be the issue.

I have also disconnected the control switches and the window will still move by itself.

Sometimes it is fine for a while and then fault kicks in again. Might go up or down - seemingly random.

I tested the voltages on what seemed to be the correct wire for that window (black and green) and was reading 2.9V or thereabouts when the fault was happening [usually 10.7 is off, 0.9V is down and 5V is up].

I'm thinking I will prob have to buy a new motor/controller unit from ebay which seems to be about £50 but I'd thought I'd check with you guys first to make sure there is not some simple and cheaper solution that I am overlooking.

I thought maybe a faulty signal/short coming from the lock (as you can close/open the windows using the driver's door lock) but then this would presumably make all the windows behave erratically and not just the driver's.

Cheers in advance.

Tom, UK

Hi Tom

On this generation of window motors there's a tendency for moisture to condense on the circuit board. It collects between a plastic connector body and the surface of the board, and tends to corrode copper tracks and sometimes form new and undesirable connections between pins of the connector and the ground plane. These may vary in their effects with temperature and humidity levels.

This type of board damage can be repaired, but takes enough time to make it not really economically sensible whilst secondhand prices are relatively low.

Try to match the second line of part number label, probably SK258... in your case, as well as the main VW group part number.

Most ebay sellers overgeneralise applicability.

Ones with VW240 or VW750 as that second line will be from Polos or T5s, and will send the glass in the opposite direction to switch commands if used in Skodas.

Edited 13 February13 Feb by Breezy_Pete

7 minutes ago, Breezy_Pete said:

Hi Tom

On this generation of window motors there's a tendency for moisture to condense on the circuit board. It collects between a plastic connector body and the surface of the board, and tends to corrode copper tracks and sometimes form new and undesirable connections between pins of the connector and the ground plane. These may vary in their effects with temperature and humidity levels.

This type of board damage can be repaired, but takes enough time to make it not really economically sensible whilst secondhand prices are relatively low.

Try to match the second line of part number label, probably SK258... in your case, as well as the main VW group part number.

Most ebay sellers overgeneralise applicability.

Ones with VW240 or VW750 as that second line will be from Polos ot T5s, and will send the glass in the opposite direction to switch commands if used in Skodas.

Awesome. Thanks so much Breezy! I think I have found the correct part . Is it relatively easy to swap in the replacement one or is there some fiddly aligning to do?

Should be fairly easy.

Be careful to pull the old one away from the door squarely once the 3 Tx25 screws are out.

They go into plastic pillars which can crack away if the thing gets on the wonk on its way off.

Thanks for the heads up!

2 hours ago, Breezy_Pete said:

Try to match the second line of part number label, probably SK258... in your case, as well as the main VW group part number.

Most ebay sellers overgeneralise applicability.

Ones with VW240 or VW750 as that second line will be from Polos or T5s, and will send the glass in the opposite direction to switch commands if used in Skodas.

Hi again. WRT matching the part numbers the closest I can find has the same main part code (6Q1959801J) and is very close on the SK number - so mine is SK258D4DRS whereas the one on ebay is SK250D4DRS. The ebay part came from a fabia whereas mine is a roomster. Do you think this will work?

Close enough, I think.

SK250... does indeed mean it was originally in a mk2 Fabia.

Only thing that may not work perfectly is one touch opening/closing if the glass height is different between these models. Direction of movement will be correct.

Thanks again Pete!

Please let us know how you get on.

Sure will. Probably take a little while for the part to come. I might try and have a look at the circuit of the original tonight before ordering the replacement if it is easy to get to (I imagine probably not!). I have some electronics experience so might be worth a look.

9 hours ago, Breezy_Pete said:

Please let us know how you get on.

Bit of an update. I took the motor/controller unit out and took it apart. Couldn't see much corrosion or moisture on the tracks but the bit under the carbon brushes/commutator I couldn't really get to or see properly (it wasn't coming apart easily and I didn't want to force it). However, it struck me that possibly the carbon spraying off the brushes might be causing some shorting on the tracks directly under it (the bits I can't see!) so I blasted air into that area through a narrow gap and then some contact cleaner and reassembled everything. Tested it for about 20 minutes and seems to be working fine but I won't know for sure whether it is fixed without a longer test. Will give you an update in a few days if it is still good or earlier if it goes bad again!

Thanks again for your help

Edited 14 February14 Feb by TomTriton

Sorry, missed your post this morning, I would've given you some tips on getting things apart without damage.

The brush dust can be considerable, but in my experience is never responsible for misbehaviour.

You have to desolder the 16-way through hole connector to find the moisture trap I was describing.

I'll add a photo or two next time I'm on my laptop.

Edited 14 February14 Feb by Breezy_Pete

7 minutes ago, Breezy_Pete said:

The brush dust can be considerable, but in my experience is never responsible for misbehaviour.

You have to desolder the 16-way through hole connector to find the moisture trap I was describing.

I'll add a photo or two next time I'm on my laptop.

Damn! I thought I'd cracked it! Thanks Pete. No rush on the pics but would be greatly appreciated.

It's possible you have sorted it, but I'd be surprised.

Here's a little vid I made recently on getting the thing apart without damage.

Without the little 'push' there's a real risk that the brushpack gets pulled out of position as you try to withdraw the motor shaft from the plastic housing, often cracking away bits of carbon brush or even completely dislodging them.

Posting this too late for you but just to spread awareness to others who may read this now or in future.

Images of board damage under the connector housing coming up in next post.

A few examples

Blimey - I see what you mean with the corrosion! I think I got lucky on the disassembly as it still works despite not doing the levering trick you show in the vid - good tip!

By the 'thru hole connector' that needs desoldering, do you mean this thing? How did you desolder? And did you manage to do some kind of workaround for the corroded tracks? Sorry for all the questions!

Yes, that thing. 14-way, not 16 like I said before.

Soldering iron and solder sucker, pin by pin.

The two 0V pins (leftmost two of your pic, I think) are tricky, as they go onto ground plane without thermal reliefs.

I use this type of sucker; fundamentally similar to most designs but the flexible silicone nozzle add-on really helps.

Repair of tracking involves peeling away damaged stuff, sometimes quite a lot of ground plane, then repairing any open-circuit tracks, and re-lacquering over the top.

Can take a while, hence it often being worth the gamble of replacement by random ebay units.

That's a good make. I have that one too. Quality Japanese tool.

Just a quick update... so far it is still ok and the issue hasn't returned. I didn't take it apart any further so I don't know whether it was badly corroded in that moisture trap area. The spray I used was Deoxit (Hosa-DeoxIt-D5S-6) which is a pretty pricey switch cleaner that I use for scratchy potentiometers on audio equipment. Based on what BreezyPete said it prob won't last and if it starts acting up again I'll find a way to restore the tracks. Will add to the post if there is any change....