Great flight today. Flew from Manassas, VA to Georgetown SC and back. On the way down, the autopilot wouldn’t hold heading. I have to use the heading mode instead of nav tracking since we still haven’t gotten that fixed yet. The latest attempt to fix the problem replaced the Turn Coordinator and autopilot. After diagnosing the autopilot, I found the TC was in a right turn even though the plane was straight and level. Disconnected autopilot. Switched to the battery for the TC (No flag by the way). Nothing. Pulled the breaker and reset. Nothing. The little airplane was just sitting there in a right turn not moving. After landing it was still frozen in this position. About an hour later it was back to normal and seemed to work properly for the trip home.