2009 DRL quit working

Got in the car the other day and the OBC displayed to check the "fog lights." They don't work with lights off or on. They are used as daytime running lights, but the car has only 45K miles. Do these LEDs go bad all at once? Headlights and turn signals work. I'd hate to have to change the entire unit, especially since tail lights are also LEDs. Will one day they go out and have to replace the entire unit, as well? Sometimes I yearn for the good old days of simple light bulbs.