Toyota 86510-AA010 Horn Assy, High Pitched

To replace the horn(s), disconnect the electrical connection and remove the mounting fasteners from the radiator support trim cover. Then take off the trim panel. When fixing the Avalon bumper, take out the part with the grill. First untangle electrical wires and unscrew the bolt holding the bracket. Installation is the reverse of removal.

Before starting electrical diagnosis, check the fuses. To test the horn, disconnect the electrical connector and connect battery voltage to the horn terminal using a jumper wire. If the horn doesn't sound, replace it. If it does sound, check for voltage at the terminal when the horn button is pressed. If there's voltage, check for a bad ground. If no voltage, check the relay. If the relay is fine, check voltage in the power and control circuits. If no voltage, inspect wiring between the relay and fuse panel. If both circuits have voltage, check the circuit from the relay to the horn button for continuity to ground. If no continuity, check for an open circuit. If continuity, check for an open or short in the circuit from the relay to the horn. To replace the horns, locate them in front of the radiator, disconnect connectors, and remove bracket bolts. Installation is the reverse.

The electrical connector needs to be disconnected and the bracket bolt needs to be removed.