Before you ask why you can't enable
this, as explained throughout this article and video, the car must have the
rain-light sensor for this to work. If the car has auto headlights and
wipers, it has this sensor. Below is a picture of the sensor. If
you don't have this square thing on the windshield, you absolutely do not have the sensor.
You can add it if you have a compatible central electric control module, see 1000q:
auto wiper-headlight sensor retrofit for details. For some reason, this useful feature isn't enabled from the factory.
As a side note, the wiper stalk is set one notch up from off for the auto function. The intermittent wiper speed sets its sensitivity when the stalk is on the auto position. The rain sensor detects water if infrared light shining out from the sensor gets bounced back into the sensor. I believe this is why the windows will automatically close after 24 hours if auto close is active. Shining the light for more than 24 hours would start to drain the battery.
Below is a demonstration of this. Only the 2005.5 model Jetta was
equipped with this on North American TDI for the mk5 generation. The new
2012 VW Passat TDI are supposed to have a rain-light sensor but I don't know if it has this
function in their control module or if it's already enabled on them.
Although 2009-2011 Audi A3 premium plus have the rain-light sensor, I am told
they cannot activate this function due to a difference in the control
module. If you find out otherwise, please post a correction and proof in the myturbodiesel.com
This is not the same as the remote fob window function where pressing and holding the unlock-lock buttons will open-close the windows. That is a separate modification, see 1000q: fob-window function for that procedure.
VCDS tool from ross tech (required)
First plug in your VCDS cable. Make sure the LED on the cable is
green. Start the software and select the control modules.
Select the 09-Central Electric module.
There are two parts to the modification. First you must enable the option in the menu. Then you must enable the auto close feature. Make sure to take screenshots to save the original coding before you make any changes.
To enable the menu option, click on long coding and then long coding helper
in the screen below. You will then see the screen bottom. You will start at Byte 0.
Each menu is a byte, each checkbox changes the bits.
Move to the right through the menus until you see the option for rain
closing and check it. The other one for inactive should not be checked.
Close the window. Click Do it! and it should save the settings. You
now have this option on the multifunction display convenience menu.
Open the CECM module
again. Click the dropbox and select item 2 RegenLichtSens.
Open the coding helper.
Click the checkbox under Byte 0, close the window, and "Do it!" to
save. Exit the CECM module and try the rain sensor function!
On mk5, it's turned on when you activate it. If you wish to deactivate it,
enter the MFD menu (see 1000q: MFD menu
options for more explanations) and go to convenience. Select
rain-closing and turn it off there.
On mk6, it's turned off by default. Select the option to turn it on.