I love it when replies say "read the manual" .Helpful isnt it !!
Daytime Running Lights:
The S40 and V40 come from the factory with daytime running lights activated. Carry out the following steps if you will deactivate them. These steps may be carried out again to reactivate and deactivate the daytime running lights as desired.
Programming for On or OFF
Turn the headlight switch to position .
Turn the ignition key in position II.
Pull the turn signal lever towards you and hold it while turning the headlight switch to position 0.
If the green light underneath the headlight switch is on the daytime running lights are on.
Do not activate or deactive the Daytime Running Lights while driving.