2009 GMC Yukon Owner's Manual - Page 195

Rear Window Wiper/Washer Z (Rear Wiper): Turns on the rear wiper. { CAUTION: In freezing weather, do not use your washer until the windshield is warmed. Otherwise the washer fluid can form ice on the windshield, blocking your vision. The rear wiper control is located on the turn signal/multifunction lever. To turn the rear wiper on, slide the lever to a wiper position. = (Rear Wiper Wash): To turn on the rear wiper wash, push the button on the end of the turn signal/ multifunction lever to spray washer fluid on the rear window. The wipers will clear the rear window and either stop or return to your preset speed. For more washer cycles, press and hold the button. The rear window wiper/washer will not operate if the liftgate or liftglass is open or ajar. If the liftgate or liftglass is opened while the rear wiper is on, the wiper will return to the parked position and stop. 9 (Off): 5 Turns the wiper off. (Rear Wiper Delay): Turns on the rear wiper delay. 3-11