Horn, Checking
WARNING: This page is about a different car, the 2011 Volkswagen CC, 2010 Volkswagen CC, and 2009 Volkswagen CC. However, it is still accessible from the selected car via links, so may be relevant.
Signal horns (High Tone Horn -H2- and Low Tone Horn -H7-) can be checked via output Diagnostic Test Mode (DTM) of Vehicle Electrical System Control Module -J519-. Refer to OUTPUT DIAGNOSTIC TEST MODE .