Anyone have an issue with their nav system not providing voice instructions during guidance to a destination? The weird part is it won't give me voice instructions for any preset destination except "Home". Also, I don't get voice instructions when I get directions downloaded from OnStar. I do get voice instructions if I do a direct address entry on the screen keyboard. If I press the "repeat" button, I will get the last voice instruction. I haven't had time to take the car to the dealer to get it checked out. I'm just wondering if it's an inadvertent setting on my part.