Horn System: Inspection

INSPECT HORN SWITCH
1. Check that no continuity exists between the horn contact plate and body ground.
2. Check that continuity exists between the horn contact plate and body ground when the horn contact plate is pressed against the steering spoke assembly.
  
  Fig 1: Checking Horn Switch Continuity
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If continuity is not as specified, repair or replace the steering wheel or wire harness as necessary.
INSPECT HORN OPERATION
Connect the positive (+) lead from the battery to the terminal and negative (-) lead to the horn body and check that the horn blows.

Fig 2: Checking Horn Operation
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If operation is not as specified, replace the horn.