Melt margarine in large saucepan over low heat. Stir in onion; cook until tender. Stir in flour, bouillon, thyme and pepper. Cook until mixture is smooth and boubly. Gradually stir in milk and water; cook over medium heat until mixture boils and thickens, stirring constantly. Add potatoes, ham and vegetables. Reduce heat; simmer 10 minutes or until vegetables are tender, stirring occasionally.