1989 Taurus turn signal

Hi, Recently, the turn signal on my car has begun to work only intermittently. It always works right after the car is started, then will stop, then often start working again. What could cause this, other than wear of the stick assembly itself? Could it be a fuse, and if so, where is the fusebox located (haven't had the car long, and I mainly use it as a train station car)? Thanks!