No matter your method, grilling corn takes about 15 to 20 minutes. However, other prep work such as soaking, shucking, or wrapping the cobs will further impact the overall time.
One option is to soak the cobs (with just the silk removed) for 10 to 20 minutes before grilling for 15 to 20 minutes in the husk, turning occasionally to cook it evenly.
For a more charred taste, grill the corn directly on the grates without the husks. Shuck the corn and place it on the grill for about 10 minutes, turning frequently as it cooks.