WAS DRIVING APPROXIMATELY 50 MPH HEARD A POPPING NOISE. NOTICED WHITE SMOKE COMING FROM STEERING COLUMN. NO FLAMES APPEARED. PULLED VEHICLE OVER AND SHUT EVERYTHING DOWN. CONTACTED POLICE AND TOWED THE TRUCK. AT THE MECHANIC'S SHOP WAS INFORMED THAT THE CRUISE CONTROL CABLE WAS PINCHED OFF AND STARTED THE ELECTRICAL FIRE. NO INJURIES REPORTED. *AK *TT