I’ve been meaning to contribute to this site for a while now, generally with knowledge I have gained whilst fixing small issues with my Audi A4 Convertible.
This article covers the cleaning of the contacts within my Audi’s electric window switches.
I had noticed that my electric windows were getting rather intermittent in operation, my rear passenger window, wouldn’t wind up at all with the switch and had to be wound up using the the large “all window” switch, also the front two windows would not “auto” up or down unless the buttons were hammered repeatedly.
The answer seemed to be to remove the switch unit and open it up to clean the contacts, and this article will explain the process I followed to do this.
I started by removing the switch unit from the door of the car, this was achieved by simply lifting the front of the switch panel (with my finger tips under the front window switches) and then sliding the switch unit forward to remove it from the car. The unit is connected to the door using a single plug, with a sprung catch that locks it into the unit, press this latch with your fingernail and wriggle the plug out of the switch unit.
Once removed the switch unit will look like this.
There are latches that hold the switches into the outer mounting plate that can be found at each end of the removed unit. These need to have a screwdriver slide down the side of them to unclip them from the outer mounting plate.
There also appears to be a clip hole in the middle of the mounting plate, but this has no corresponding latch on my switch unit.
Once the two switch unit and the mounting plate have been unclipped these are the parts you will be left with.
Next step is to remove all the switch rockers from their pivots. This is done by carefully levering the rockers away from the pivot points, the rockers are quite thin plastic on the sides and so can be flexed away from the pins they pivot on.
One pivot pin is large…
The other is small.
Once all the rockers have been removed you will have the main switch unit showing the “push pins” that activate the internal contacts of the switches.
The next tasks is a little more tricky… it appears from first looks that the switch unit is sealed and that there is no way into it, this put me off the first time I attempted this job and I put all the rockers back on and placed the unit back in the car. This time however I decided to have a closer look.
I found that there were slots in the under side of the switch unit and looking more closely I could see internal latches that seemed to be holding the top plates with the push pins onto the bottom panel of the unit.
I stuck a strong but narrow (and fairly thin) piece of metal into one of these whilst putting pressure on the top plate, by sliding a screwdriver down the side of the plate on the top and lifting gently. After wiggling the piece of metal in the slot a bit I managed to free one of the catches. I did this for the other three catches that held the plate (there are four catches per plate and can be seen in the picture above).
Be cautious here as when the plate is removed all the switch components connected to the board will probably fall out onto you work area. Carry out this task over a clear workspace!
The first plate came off and this is what the switch unit looked like.
The latches are shown in these two pictures and might make it easier to see how the plates are held to the back plate of the switch unit.
I moved onto the next four catches and the second plate came off (this plate had a longer flat area joining up to the first plate).
Then finally I removed the last plate using the same technique.
The components that fall out of the backs of the plate look like this.
The items are (left to right) the rubber “spring” membrane, the sprung click contacts and the push pins.
Once the plates are removed the PCB will be visible.
This can be cleaned with an ear bud and some PCB cleaner (or brake cleaner would work). To do this I removed the PCB from the back plate of the switch unit, but the job could just as easily be achieved with the PCB in situ.
The ear bud is soaked in Cleaner and then wiped over the contacts to clean them up. I actually got quite a lot of dirt off of mine as the ear bud was quite dirty after I’d finished.
I then re-assembled the plates for re-fitting to the back plate of the switch unit.
This process consisted of fitting the push pins.
Then the membrane (note the holes in the membrane and the missing single pin on the plate!)
And finally the sprung contacts.
I had decided to clean the contacts once they were installed on the plate, which meant there was less likelihood of my contaminating them with grease off my fingers when they were re-installed on the back plate.
This was done by wetting an eat bud with cleaning fluid and wiping the contacts in situ.
I then added the second set of pins, membrane and contacts, cleaned them and this plate was ready for re-installation into the back plate.
I re-assembled all the plates in this way ready for installation into the back plate and simply left them “upside down” on my work area so that the components didn’t fall off them.
Re-fitting of the plates needs to be done in the reverse order of removal… i.e. the last “long” plate needs to be fitted first, this is due to a step that exists on each plate that mates up to the next plate along. This step sits on top of the edge of the previous plate.
So… start with the “wide rocker” plate (central contacts).
The plate needs to be held upside down (with the contacts facing up) otherwise everything will fall off the plate. The back plate has to be lowered onto the front plates and then pressed home all the while keeping the plate nice and level.
Then the same process has to be done for the middle twin rocker plate.
And finally the end shorter twin rocker plate.
Next install the rockers back onto their pivots. Be certain to make sure that the switches are correctly placed, they are left and right handed and angle into the middle of the switch unit (as shown in the next image).
As a point to note… there are some small blocks seen in the top face of the switch unit that are behind the middle set of rockers. These appear to stop the rocker from being lifted enough to activate the “secondary” auto up mode of the rear windows. This I guess is a safety feature, but I wonder if those blocks were removed whether the rear windows would auto up like the front ones!?
Once all the rockers are back in place. Simply re-fit the whole switch unit back into the mounting plate.
Re-fit the connector from the door into the back of the switch unit and slot the whole thing back into the door (rear first, clip at the front).
Try your windows to see if all is well.
After carrying out this job, my “faulty” rear window switch worked fine and all the auto features of the front windows worked flawlessly!