One problem related to windshield wiper/washer has been reported for the 2006 GMC Envoy. The most recently reported issues are listed below.
Front windshield washer nozzle failure, both (left and right). 1st event noted in 2009 when vehicle had 32000 miles, this is the 2nd event. Nozzles stop spraying washing fluid effectively, preventing driver from cleaning the front windshield in high debris conditions, reducing visibility and posing a driving hazard specially in high debris / insect areas in non-optimal lighting conditions such as nighttime driving or when the vehicle is aligned towards the sun or other light source. Previous event required replacement of the nozzles, it is not caused by obstruction as plenty of fluid still flows out of the nozzle (just not in the necessary pattern).