One problem related to rear window wiper washer has been reported for the 2006 GMC Envoy. The most recently reported issues are listed below.
2006 GMC Envoy; replaced timing chain, failure of fuel pump, oil pump, electrical system driver's side door, washer fluid pump, tailgate latch failure and rear wash fluid line failure. Replaced or fixed all issues except, tailgate latch, rear washer fluid line, oil pump issue and SUV will not hold oil pressure.