PREPARATION:

1. Remove husks and silk from corn. Place in large bowl and cover with cold water; soak 20 to 30 minutes. Remove; wrap in foil. Grill on covered grill over medium-hot coals 20 to 25 minutes or until hot and tender, turning over halfway through grilling time. Remove kernels from cob. Set aside.
2. To grill zucchini, spray zucchini on both sides with cooking spray. Grill on uncovered grill over medium coals 4 minutes or until grillmarked and tender, turning once during grilling. Cool; cut into bite-size pieces. Set aside.
3. Cut potato in half lengthwise; grill potato halves on covered grill over medium coals 15 to 20 minutes or until potato is tender, turning over once during grilling. Cut potato into cubes.
4. Melt margarine in large saucepan over medium heat. Add onion; cook and stir 5 minutes or until tender but not brown. Stir in flour, salt, thyme and pepper. Cook and stir about 1 minute.
5. Stir broth and milk into flour mixture. Cook and stir over medium heat until mixture begins to bubble; continue cooking about 1 minute more. Stir in corn, zucchini, potato and cheese. Reduce heat to low; simmer, uncovered, until cheese is melted and mixture is hot, stirring constantly. Garnish as desired.