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Roof / rear window problem

4041 Views 10 Replies 6 Participants Last post by  voxmagna
Hello, I have a problem with the left rear window of my car.
The window refuses to move with the switch on the door and the roof wont go down, but I can operate the window with VCDS using the test activate function, when I make the window go down and and back up, the roof will then open the window (again) and the roof will go down. But the roof wont come back up until I close the window first with VCDS. the roof switch then opens the window, closes the roof then closes the window. There is no fault codes for the window or for the roof.
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Does the windows switch work from the passenger side ?

Would be unlikely both have failed so if it works suggest the switch might need to be swapped out

Might be worth trying to remove the switch and give the contacts a clean as water may have got in


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OP wrote that it's the left rear window, so the only two switches are the individual window switch and the all-windows switch. Worth checking them both though.
Unlike other non-cabriolet cars the EOS window system uses TWO controllers. The manual door switches and vcds are activating the windows through the convenience module. But the roof controller has it's own communication system to the rear window motor controllers. This is what makes EOS electronic parts different to other cars like Golfs & Passats! The only conflict fault I can think of is if the window switch or wiring has a permanent short (or the rocker is stuck down). But I might expect the window to then operate at every key on? :confused: You could remove the door panel and test the switch wires aren't permanently closed using a multimeter.

I see you have done a scan which shows there are no controller faults? Belt and braces you could remove the left side trunk trim and clean all the roof controller connectors. IMHO you usually get a fault code if you try to activate the roof and it won't start for some reason. VCDS isn't perfect in the EOS roof department. V.W VAS is more comprehensive and sometimes allows dealers to fix faulty firmware in modules through the OBD port.

If the rear window controller shows a fault like 'no communication', don't tear the car apart to replace it. :( Take it to a V.W dealer and get them to check (reflash) the firmware code in the rear window motor controller. If they can't do it, then the motor controller is really bad and you are into an expensive teardown to replace it. It may seem strange that the window sort of works, but the problem as I see it could be code corruption in the motor module. :(

Have you been doing any jump starts, on car battery charging, or let the battery go flat? :confused:
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The switch for the front passenger window on the drivers door panel doesn't return properly it's getting stuck down. I am going to buy a new switch panel and see if it helps as both windows are on one fuse each side, maybe it's affecting the rear window or the rear switch is faulty.
You can buy the switches seperatly. I found water from when the windows drop to allow the door to open dripped onto the switches and corroded them out. Once replaced all was good after.
It was the rear switch that was corroded inside I replaced it with a front switch as it was cheaper the only difference is it has the extra click to move the window down in one go (i'm not sure if this works) roof now working. :)
Hi all,
I am reviving this thread for the following reason:

The left rear window lifts and lowers correctly when using the driver's door individual window switch or the master switch. This function also shows up all OK on my OBD-11.

However, when operating the roof retraction, the left-rear window only goes down 50% and the roof retract stops. But, if I manually lower the left rear window via switch, then the roof retraction process continues.

BTW, this may be tied to another thread I posted last year in that the car still thinks it's a 4-door. I bought the pro version of OBD-11 and tried to recode the car into a 2-door model without success. It seem this is a dealer-only reflash?
You cannot recode it from 4 door to 2 door, the problem is a corrupt copy of firmware in the rear window controller which remains stored. V.W use the same module in 4 door cars but for this particular module, it takes on EOS 2 door personality from the engine ECU model variant the first time it boots from new with empty memory.

You have 2 choices, get a dealer to reflash or if you can lay up the car for week, leave the battery disconnected. After some days (Yes a long time), the rear window modules should have forgotten their bad 4 door personality and re-learn EOS 2 door when the battery is connected. This assumes no other internal fault.
Hi Voxmagna,
Yes, thanks for that reply. That's what I was afraid of. I had thought that buying the OBD-11 "pro" package would let me re-flash the firmware. I will try the disconnect idea. I also have read that shorting out the positive to chassis ground can also have the same effect. This whole mess happened last year when the previous battery died. Every time I have a dead battery, I have a raft of new faults.

This thread is also tied to a previous one where the car's dashboard icon shows 4-doors and the interior lights stay on...
I also have read that shorting out the positive to chassis ground can also have the same effect.
You didn't get that from me! I've already posted my explanation. These modules can have an internal series diode for reverse voltage protection or a voltage regulator which can do the same thing. Grounding the battery wires will do nothing. Internal mos memory can store its (corrupt) data with a voltage line as low as 2 volts or less. They could easily have designed the module to self discharge, but I suspect they didn't because it allows the module to keep its data stored during a battery swap?

If you don't want a dealer to go through the reflash process, or wait a week, you can go through the pain of removing the module, open the lid and using a 10 ohm resistor go around all the on board chip capacitors discharging them until you measure <100mV anywhere. When you put it back at key on, it will make a fresh copy of the correct code from ROM and store it in its working memory.
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