Cal. Probate Code § 1602

(a) The Legislature hereby finds and declares that guardians perform a critical and important role in the lives of minors, frequently assuming a parental role and caring for a child when the child’s parent or parents are unable or unwilling to do so. (b) Upon making a determination that a guardianship should be terminated pursuant to Section 1601, the court may consider whether continued visitation between the ward and the guardian is in the ward’s best interest. As part of the order of termination, the court shall have jurisdiction to issue an order providing for ongoing visitation between a former guardian and his or her former minor ward after the termination of the guardianship. The order granting or denying visitation may not be modified unless the court determines, based upon evidence presented, that there has been a significant change of circumstances since the court issued the order and that modification of the order is in the best interest of the child. (c) A copy of the visitation order shall be filed in any court proceeding relating to custody of the minor. If a prior order has not been filed, and a proceeding is not pending relating to the custody of the minor in the court of any county, the visitation order may be used as the sole basis for opening a file in the court of the county in which the custodial parent resides. While a parent of the child has custody of the child, proceedings for modification of the visitation order shall be determined in a proceeding under the Family Code.