1In a bowl, mix the mayonnaise, minced garlic, and lemon juice. Set aside in the refrigerator.
3Brush vegetables with olive oil on each side. Brush grate with oil. Place bell peppers and zucchini closest to the middle of the grill, and set onion and squash pieces around them. Cook for about 3 minutes, turn, and cook for another 3 minutes. The peppers may take a bit longer. Remove from grill, and set aside.