Assuming you would like tips for troubleshooting a turn signal that will not shut off:
1. Check the vehicle's fuse box to see if the turn signal fuse has blown. This is usually indicated by a burnt-out wire or a broken connector. If the fuse is blown, replace it with a new one of the same amperage.
2. Inspect the wiring harness for any loose, damaged, or corroded wires. If any are found, repair or replace them as necessary.
3. Locate the turn signal relay and check to see if it is defective. A faulty relay will often cause the turn signals to stay on constantly or intermittently. If the relay is defective, replace it with a new one.
4. Check all of the bulbs in the turn signal system to see if any are burned out or broken. Replace any defective bulbs with new ones of the same wattage and type