How to diagnose horn malfunctions? on 2004 Toyota Sienna

My 2004 Sienna has a dual-tone horn. The high pitch horn has suddenly stopped working; only the low-pitch horn still works. How to diagnose this problem? What must I check? Thank you.

by in Wesley Chapel, FL on October 08, 2012
2 answers 1 comment
ANSWER by , October 08, 2012
CK PWR AT THE FAULTY HORN IF YOU HAVE PWR RUN AX. PWR TO HORN AND SEE IF IT WORKS IF NOT REPL HORN
COMMENT by , November 24, 2014
have not checked horn but what is the process to test horn
ANSWER by , November 24, 2014
no horn but fuse and horn relay are good