269So as to ensure proper operation of the rainsensor 3, the sensor field must be free fromdust and dirt and the windsc reen washsystem m ust be opera ted a t regularintervals. Vehic les with rain sensor 3 can b eidentified by the sensor field near the top ofthe w indscreen.Service setting for front windscr een wip er(e.g. for cha nging or cleaning the frontwiper b la des).Within 8 seconds of switching off theignition, press the windscreen wip er stalkdownwards. Release the windscreen wip erstalk as soon as the w ip er blad es arevertical.Wiper bl ades on the windscreenActivating serv ice p osition, see precedingcolumn. Lift wiper arm. Press the releaselever a nd detac h the wiper blade.