2005-2008 Honda ATV TRX500FA/FGA Fourtrax, Rubicon Factory Service Manual, Page 465Get this manual
LIGHTSMETERSSWITCHES
HORN SWITCH (U type only)
Disconnect the horn switch wire connectors'05'06 shown:
CONNECTORS Check the continuity between the connector terminalsThere should be continuity when the horn switch is pushed, and be no continuity when the switch is releasedHORN SWITCH