Not sure on exact cost to fix the bulb as it was fixed with the turn signal stalk issue that I made in a different post. Could have replaced it myself if GM had not made it so difficult to replace it by having to take off the front wheel and front fender so I can access the headlight to replace the bulb in question. Mechanic pulled the bulb out and stated it was black. No big deal as light bulbs don't last forever. But I wish it was easier to replace like my old Impala.