Genuine Lexus ES300 Horn

Lexus ES300 Horn Parts Questions & Answers

• Horn Assy, Security
  86510-33110
  Q: How do I perform horn diagnostics, troubleshoot issues, and remove the horn in the Lexus ES300?

  A: Disconnect the electrical connector from the horn and test it with battery voltage. If it doesn't sound, replace it; if it does, check for voltage at the terminal when the horn button is pressed. If there's voltage, check the ground connection. If not, inspect the horn relay and its wiring. If both have voltage, test the circuit from the relay to the horn button. If absent, check for an open circuit or replace the horn button. If continuity exists, check for an open or short in the circuit from the relay to the horn. For removal, disconnect the connector and remove the bracket bolt. To reinstall, switch the removal steps going from the last step to the first step.