Toyota 86510-04010 Horn Assy, High Pitched

The horn unit on Tacoma models is placed directly behind the grille between the radiator and the right headlight. Plug the electrical connector out and apply power from the battery to the two terminals by using jumper wires to see if the horn works; replace it when it fails to sound. To diagnose the horn problem check for power supply at the terminal when you push the horn button. If a good power supply exists test the ground connection. Check the horn relay which generally takes the form of either the four-terminal or externally grounded three-terminal configuration when no voltage is detected. When the relay works test if both supply and control wiring circuits receive power from between the relay and fuse panel connections. When voltage reaches both relay circuits press the horn button then test for ground connection in the circuit from relay to button; a failed ground requires open circuit assessment and if that test succeeds replace the horn button. Based on this information examine the horn button first then see if a break or ground fault exists between the relay and horn connection. Additionally normalize verbalization when feasible. Free the horn electronics and take off its bracket bolt to disconnect it from the vehicle body. Secure the bracket with threads on the old horn before mounting it onto the new unit following the steps that reversed removal.