406 d9 drivers window fixed

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Location: Gloucestershire uk

406 d9 drivers window fixed

Post by positor1 » Mon Jan 31, 2011 5:02 pm

Perhaps this could be moved to KB forum.

I have read a lot of posts about problems with the drivers door window not working correctly.
Having followed the suggestions ( resetting ecu ) to no avail I decided to investigate the switch further as it seemed to be the cause.

I have attached pictures of the switch assembly,
PLease note this is the newer D9 406 not a d8!

Symptom: pressing the drivers window down switch either manual or auto position results in no operation or attempts to wind window up further ( evident by a faint click heard after a second or so)
Continual pressing will eventualy result in window opening.
NB it could be possible that these symptoms could be caused by other factors so use your judgement.

Testing for switch fault: (bypassing the switch)
Clearly if the ecu (management system) motor or wiring are faulty then bypassing the switch will not cure the fault, so this should be the 1st thing to try (imo) (in my opinion)

To remove the switch pack, 1st . In the base of the trough you put your fingers in to close the door and store rainwater and fags, you will see a rubber cover, prize this out and either store safely or throw it now to save time searching at the end!
Undo the torx screw and prize the whole trough and switch pack up.
It is held by spring clips at the narrow front end and either side of the switches.

You will see three connectors underneath. The windows are on the largest of these connectors, the one with a red locking clip.(see pic 1)
Pull the red clip to release this connector, you may find it easier to remove the other two smaller ones but not necassary.

The connector (the part with the wires attached) has 16 positionswith 14 wires connected. They are numbered 1 through 16.
To similate a down press of the switch you need to short pin 1 (Mine had one of two orange cables at pin 1) to pin position 11 (eleven which on mine has a red wire connected to it)
With ignition on the window should go down.

To simulate an up press you need to short pin 1 to pin 12 ( one of the yellows in my case)

If this operates the window every time then the switch pack is faulty and needs the following, if not tehn back to the forums sorry.

How it all (seems) to work:
There are effectively four switches under the drivers door button, one each for up/down, manual /automatic, but confusingly they only contact (short out) a combination of three wires, those being on pins 1 (orange? which i assume is the supply) and pins 11 and 12.
As above to wind the window down manualy to need to short pins 1 and 11, when you press the switch to the auto position- pin 12 also becomes live, so for full auto down the switch 1st makes (shorts) pins 1 and 11 and then also makes pin 12 ( yes the very pin that on its own would give you an upward wind!
Out of interest or to amaze you further an auto up wind connects pin 1 (supply?) to pin 12 and then after also makes pin 11.
The same three connections but in a different order.
This is acheived by the switch contacts being of differing heights, so one makes contact before the other (see pics)

So the switch is faulty and you are not rich? lets fix the sucker!

remove all the connectors and take the switch pack somewhere comfortable to work on, you are going to break some of the fixings, beleive me but the switch seems happy to stay together after.

stage 1.
remove the round mirror adjust button by prizing upwards, it is quite stiff to remove and i suggest two prizers,(kitchen knives) one either side to avoid snapping it.

stage 2.
Seperate the trough part of the switch pack from the switch unit.
See pic1, on the side of the unit closest to the top face you will see three clip positions along its length(left one next to thumbnail)
just big enough to fit a medium screwdiver and theoreticaly push in to disengage. This is where you are going to break pieces but i see no way of avoiding it, again it seems of no consequence.
When you have given up trying to hold the thing and push three clips in at once, try breaking the minute piece of plastic that the clip sits against.
It helps to lift the front window switches as you pull the assembly apart (after snapping those stupid 1mm clip retainers.

stage 3,
now seperate the switch assembly to reveal the dirty contacts.
Underneath the assembly you will see 8 plastic clips which you need to gently pull back, I found releasing a couple and sliding a knife ( i mean a dedicated specialist tool) between the pieces as i went helped a lot but not that difficult to acheive.
you now have three main parts, see pic. the top part with the finger well, the switch presses and the part with the green and white physical switches.

http://www.flickr.com/photos/31242942@N ... otostream/

stage 4.
The contacts we are interested in are under the smaller green rubber with four lumps, pull this off noting the orientation (though there are 4 offset pins that go through the rubber to assist correct orientation.

http://www.flickr.com/photos/31242942@N ... otostream/

You will now see the circuit board contacts.
At the corrosponding positions for the switch rubber membrane you will see 8 raised nipples, this is where physical contact is made when the membrane and its copper disc contact is pushed down, you may notice that one or two have become copper coloured as opposed to steel looking, this is where the contacts and the electrical spark have taken the tinning ( silver colour) off ( not off of thankyou america) and could cause us a problem in the future. It would be nice to recoat any bare copper contact positions but I can see that causing more problems for those not good at soldering so lets bypass.
You will also see years of dirt on the tracks and also on the membrane contacts ( turn the green membrane over and you can see where the copper discs have contacted the silver tracks.

http://www.flickr.com/photos/31242942@N ... otostream/

Clean all the contacts and the copper coloured discs in the membrane (very careful with the membrane as discs must only be glued to it and tearing one off will cost you a new switch assembly. the spots on the copper discs are hard to clean off but clean as much as you can as a bad contact will re create the fault quite quickly.)
I used propper switch cleaner because i have it, PLEASE DO NOT use anything flammable.

Stage 5: re assemble

Quite straightforward but i recommend that you seal the outer edge of the green membrane to prevent rain getting underneath and ruining your hard work over time.
For this i used plumbers mate, (non setting silicon seal) A word of caution though, dont use silicon that sets ( you may need to do this again one day) and dont get any on the copper discs under the membrane causing a bad contact, the tiniest smear all around the edge is enough, if you can see even small lumps then remove as when you assemble it will spread under the membrane.
Last edited by positor1 on Mon Jan 31, 2011 8:25 pm, edited 1 time in total.