Volvo advises that the horn units can be accessed by removing the grille, but due to the difficulty of grille removal with the bumper in place, it is recommended to remove the front bumper to prevent the risk of damage. Once the front bumper is removed, unclip the plastic cover from the bumper mounting bar, unbolt the horn from its bracket, and disconnect the wiring plug as the horn is removed. Reinstallation is the reverse of the removal process.