California Code, Family Code - FAM § 3105

(a) The Legislature finds and declares that a parent's fundamental right to provide for the care, custody, companionship, and management of the parent's children, while compelling, is not absolute. Children have a fundamental right to maintain healthy, stable relationships with a person who has served in a significant, judicially approved parental role.

(b) The court may grant reasonable visitation rights to a person who previously served as the legal guardian of a child, if visitation is determined to be in the best interest of the minor child.

(c) In the absence of a court order granting or denying visitation between a former legal guardian and a former minor ward, and if a dependency proceeding is not pending, a former legal guardian may maintain an independent action for visitation with the former minor ward. If the child does not have at least one living parent, visitation shall not be determined in a proceeding under the Family Code, but shall instead be determined in a guardianship proceeding that may be initiated for that purpose.