First read and observe the introductory information
and safety warnings
The trailer stabilisation function is an extension to the electronic stabilisation programme (ESP). It helps, in conjunction with the driver steering recommendation function, to reduce the risk of rocking when towing a trailer.
An active trailer stabilisation function can be recognised
when the ESP indicator lamp
in the instrument
cluster lights up for approximately two seconds longer than the ABS indicator lamp.
Requirements for trailer stabilisation
or
in the instrument cluster is not
lit up. 
WARNING

WARNING
Towing a trailer
Retrofitting a towing bracketVolkswagen Touran Owners Manual. Main beam control
First read and observe the introductory information
and safety warnings Main beam control (Light Assist)
The main beam control switches the main beam on and off again
automatically within the limits of the system depending on environmental and traffic
conditions as well as travelling ...
Volkswagen Touran Service Manual. Cigarette Lighter Illumination Bulb -L28-, Removing and Installing
Note
On some vehicle equipment levels, socket illumination is via
Light Emitting Diode (LED) instead of a bulb. These LEDs are
integrated with the illumination housing and cannot be serviced
or replaced separately.
...