Call a criminal defense attorney. An attorney can contact the police and the courts to find out if you need to turn yourself in on a warrant. It is always better to show up at the courthouse to voluntarily turn yourself in, with an attorney by your side, than to wait until you are picked up by the police. The judge is unlikely to set a low bond amount If you are arraigned on video from the jail house while wearing an orange jumpsuit.
If you call the police yourself, they will just tell you to come down to the station house. An attorney can walk you into court instead.
I would agree that an attorney could assist you in contacting the St. Clair Circuit Court, or the surrounding district courts as well as the St. Clair County Sheriff or other arresting law enforcement in order to find out status of your warrant. Once you have that information, an attorney should accompany you on the arraignment on the bench warrant. Be sure that you have sufficient fees to take care of the original fines and costs as well as any others that may have been tacked on.
An attorney in the Port Huron area would be best as you will want to hire someone with some gravitas with the local court over there. I was just in front of Elwood Brown today and appear in the 72nd District from time to time, although my office is in Clarkston.