Son is a dependent but has a part time job, does he file his own taxes?

[xmasbaby0]

If your dependent has a W-2 for his after-school job, etc. you do not include the information on your own return. You can still claim your child as a dependent on your own return.  He/she can file his own return for a refund of some of his withheld wages (he won’t get back anything for Social Security or Medicare), but MUST indicate on it that he can be claimed as a dependent on someone else’s return.  (Supervise this closely or prepare it for him!)

If your dependent’s earnings were over $400 and were reported on a 1099Misc then he must file a return and pay self-employment tax for Social Security and Medicare.  You may want to use this version of TT for that:

https://turbotax.intuit.com/taxfreedom/

[TomD8]

He must file his own tax return if his earned income was over $6300, or if he had net earnings from self-employment of at least $400.

Even if his income fell below these thresholds, although not required he'd have to file a return if he wanted a refund of any withheld taxes (as explained above by xmasbaby0).

If he does file his own return, that does not preclude you from claiming him as a dependent if he meets the IRS criteria.