I have a seatbelt ticket I haven't paid in a year and a half

No - you will have to get warrant lifted and pay for ticket . Some courts are allowing community service in lieu of fine .

You need to contact a criminal defense attorney in your area to make sure a warrant wasn't issued for your arrest if you failed to appear in court. I don't practice in CA, but in KY if you failed to come to court and failed to pay the fine and costs, in addition to a warrant, the DOT would be notified and your drivers license suspended until you took care of it. Get counsel.

If you failed to appear on the ticket, your license is probably suspended because of that. The good news is that once you appear and the failure to appear is lifted, you can get your license reinstated and work on paying back the fines. If you failed to PAY, and your license was suspended because of that, you'll have to pay off the entire amount before they will release your license. Either way, you'll have to go to court to get this cleared up and get started down the path of fixing this.

I agree with the previous answers here. It's best to set a date and go to court. Or, seek legal counsel. Something like this will not go away, and action needs to be taken so fines don't increase.