WHILE PUTTING THE VEHICLE IN 4-WHEEL DRIVE IT BEGAN TO ACCELERATE. VEHICLE RAN INTO A GUARD RAIL AND ROLLED DOWN INTO A DITCH. OWNER CONTACTED THE DEALER, WHO SAID IT WAS THE FAULT OF THE DRIVER. LATER, DEALER CONTACTED THE OWNER, AND INFORMED HIM THAT THE 4-WHEEL DRIVE KEY WAS BROKEN. *AK *BF *NM