After having my '06 in the dealership 4 times now for cruise control failure, I wanted to let everyone know that if you run into this issue that most likely it will be the control solenoid valve and transmission module ON the transmission that will most likely be the cause. Once this module sends a false signal it will lock out your cruise control input and render the cruise control useless until the dealership can reset. The valve body of the transmission is being replaced. Good thing this is still under warranty. But until this valve was replaced, the dealership kepted throwing parts at the problem instead of dealing with the whole system one time. Go figure.
