The four wheel drive actuator on top of the transfer case failed- actuator is vacuum actuated and when it failed it allowed transfer case fluid to be drawn into the vacuum system of the vehicle causing problems with four wheel drive engagement and disengagement. But the worst problem is that the fluid caused the heater controls, also vacuum activated, not to work properly so that the vehicle windshield could not be defogged or defrosted, which is a safety problem because of the lack of visibility. It is a known defect with this vehicle but G.M. refuses to acknowledge the manufacturing problems. The dealer had to replace all the actuators (5), the vacuum tank, the vacuum lines and the heater control.

- Templeton, MA, USA

105 TO110 degree temperature air blowing onto feet with all heater controls shut off and in the coolest temperature setting. Dealer said this is normal, and provided a service bulletin from GM stating that on these trucks this situation is because of the pressure created by the wind blowing over the windshield, forcing the air into the passenger compartment. Very uncomfortable to drive.

- Clinton Township, MI, USA