My son is turning 18 in May & graduating high school in June. He will be a full time student in college, unmarried, and not self-supporting. What can I do to enforce his father to continue paying child support? Is there a way to file my petition in court?

Generally speaking, you can't. In California, support generally terminates once the child has reached 18 and graduated from high school, or reached 19. Neither parent is obligated to pay for a college education or college related expenses. The exact point to termination will depend on how your support order is worded, but I do not see you being able to extend support past that point unless your support order or divorce decree specifically calls for your ex to share in the expense.

It ends and that is the law. Now if you wish you can discuss your child's furthering of education and if he would like to contribute but there are no laws that make it mandatory.

This is spelled out in the original support order. If the support order specifies until school is finished, then he continues to pay. If it doesn't then statutorily it ends when he turns 18 or finishes HS.