I am not sure how he finds his jobs. We are not on speaking terms and prior to our divorce and the child support order, he never worked 1099. During the last trial, he stated he had signed with two companies that regularly hires 1099 computer techs for work. Since then he has quit those two companies, moved to another one and quit that one.
He will never voluntarily pay child support. The courts will have to provide the incentive, which is why the child support division was attempting to revoke his driver's license. Yes, he can't work without it, but while working he certainly is not paying child support. I actually received more child support during the six months he was on unemployment than during the six years he was working. So trying to stay ahead of his employment is nearly impossible; he will just switch companies again.
Another option is to file an RFO wherein you request that your ex provide specific notice to you (or DCSS) as to discussion and agreements re employment. For example, within 24 hours, provide x,y,z as to any discussions regarding possible employment and a,b,c (correspondence, contracts, e-mails, etc.) as to the offering and acceptance of any job. It must be very specific.
The point here is that if he is ordered to comply with such notice requirements, and he doesn't comply, and you can prove that he did in fact secure work, you can bring a contempt. And, this type of contempt will be much easier to prevail upon than an ordinary contempt based on failure to pay. (And, btw, I assume you are well beyond the three year statute of limitations on a contempt for non-payment, but, if you get the type of order I'm suggestion, you'll have a new statute of limitations (probably two years), as to his failure to comply with the notice requirements. If you do get such an order, and, he does, in fact, comply, then you (or DCSS) can serve the IWO on the new principal who is retaining his services as an independent contractor. Hope that makes sense.