To replace a turn signal light, remove the light housing cover, unscrew the light socket from the setting, remove the old bulb and replace it with a new one, and then replace the light socket and housing cover. Make to use the correct type and shape of bulb; check the car's manual or bring the old bulb with you when purchasing. Wear protective gloves to avoid cutting your hands on broken pieces.
To remove the light housing cover, check the manual for vehicle-specific instructions. Most covers come off easily with only a few screws. For front end turn signal lights, it may help to turn the wheels in the opposite direction of the light before starting.
Remove the light socket by gently pulling it or twisting it out of its setting. For a round bulb, remove it from the socket by pushing it gently, and push the replacement bulb in the same way. For a cylindrical bayonet bulb, locate the small tab locking it in place, and push it in gently. Turn the bulb counterclockwise to remove it. To replace it, push the new bulb in, and turn it clockwise until it clicks into place.
When the bulb is in place, wipe it with a clean towel to remove any oils that may have transferred onto it, which can decrease the life of the bulb.