Passenger headrest deployed randomly and unexpectedly without warning during normal forward vehicle operation striking the passenger in the head. Vehicle was not in traffic or in contact with any other vehicle or object. Vehicle has no accident history or air bag deployment history. No warning lights and no warning prior to deployment. Owner is on summer holiday in Colorado. Owner contacted local Colorado dealer and was advised the headrest is not a repairable item and as such will require replacement. Dealer estimated repairs to be approximately $1,100. Part will need to be ordered and dealer could not estimate ETA for the part.