Even though child support and visitation/access arise out of the same order or custody paperwork-- one is not contingent upon the other. Until a parent's rights are terminated or restricted, they have a right to have access to their child.  Even if a dad got behind on child support, he would still have the right to see his child as set out in the court's orders.To answer your question more directly, if a court order set out regular periods of visitation for dad and mom refused to allow dad to see the child on his designated days, then mom would be subject to a contempt action or motion to enforce.  She could also be charged with felony offense of "interference with child custody."  This offense includes situations where one parent keeps a child even though they know that it is the other parent's turn for visitation.