Examination
1. On cars "Toyota 4 Runner/ Hilux/ Surf" there are 2 horns installed on both sides of the radiator.
2. To check, disconnect the connector and connect the battery directly to the signal. If there is no sound, replace the signal.
3. If there is sound, then check the voltage at the output when you press the signal button. If voltage is present, check the ground connection.
4. If there is no voltage, then check the relay. Please note that horn relays generally have 4 or 3 outputs (3-pin relays have an external ground connection).
5. If the relays are OK, then check the voltage at the relay outputs. If there is no voltage, then check the wires from the fuse to the relay.
6. If there is voltage at the relay outputs, then press the signal button and check the ground connection between the relay and the button. If there is no open, then replace the signal button.
7. If the circuit closes to ground through the button, then check for an open or short circuit in the circuit from the relay to the button.
Replacement
1. To replace the sound signal, disconnect the connector and unscrew the bolt (indicated by an arrow).
2. Remove the signal and install a new one.
3. Further installation is carried out in the reverse order.