1. Safety First:
* Disconnect the battery's negative terminal. This is crucial to prevent accidental shocks or further damage.
2. Identify the Horn Relay:
* Consult your Cadillac Eldorado's repair manual (a Haynes or Chilton manual is a good investment). This will show you the location of the horn relay. It's often located in a fuse box, under the hood or inside the car.
* Visually inspect the relay: Look for any obvious signs of damage, such as burns, melting, or loose connections. If you find damage, replace the relay with a new one of the same amperage rating.
3. Check the Horn Wiring:
* Trace the horn wiring: Your repair manual will show the wiring diagram. Carefully follow the wires from the relay to the horn(s).
* Look for frayed or damaged wires: Check for any exposed wires, breaks in the insulation, or areas where the wires might be rubbing against metal parts. Repair or replace any damaged wiring.
* Check for corrosion: Corrosion at wire connections can cause shorts. Clean the connections with a wire brush and apply dielectric grease to prevent future corrosion.
* Pay close attention to the ground connection: A poor ground connection is a common cause of electrical problems. Make sure the ground wire connected to the horn is clean, secure, and has a good connection to bare metal.
4. Inspect the Horn Itself:
* Disconnect the horn's wiring connector.
* Visually inspect the horn: Look for any signs of damage, such as corrosion, cracks, or loose connections.
* Test the horn (with caution): After disconnecting the horn wiring, carefully use a multimeter to check the horn's resistance. A very low resistance might indicate a short *within* the horn itself. If the horn is bad, replace it.
5. Test the Steering Wheel Horn Contact:
* With the horn relay and horn disconnected, use a multimeter to check the continuity of the horn switch in the steering wheel. You'll likely need to access the steering wheel assembly (potentially requiring removal). This is more involved and may require professional assistance. A short here could be due to worn contacts or damage within the switch itself.
6. Test the Horn Circuit with a Multimeter:
* Use a multimeter: With the horn relay connected, use your multimeter to test the voltage at the horn's connector. You should have battery voltage when the horn button is pressed. No voltage indicates a problem upstream (relay, wiring, or steering wheel switch).
Important Considerations:
* Professional Help: If you're not comfortable working with car electrical systems, it's best to take your Cadillac to a qualified mechanic. Improper wiring can lead to further damage or even fire.
* Repair Manual: A repair manual is essential for accurate diagnosis and repair. It will provide detailed diagrams and specifications.
* Safety: Always disconnect the battery's negative terminal before working on any electrical system.
By systematically checking each component – relay, wiring, horn, and steering wheel switch – you should be able to locate and fix the short in your 1992 Cadillac Eldorado's horn circuit. Remember safety is paramount!
