If you need to replace or upgrade your car’s horn system, you may need to wire a new 12v horn relay. This article will guide you through the process of wiring a 12v horn relay, including a wiring diagram, frequently asked questions, and tips for troubleshooting.
What is a 12v Horn Relay?
A 12v horn relay is an electrical switch that controls the operation of a car’s horn. It is used to amplify the power that the horn receives from the car’s electrical system, resulting in a louder and more effective horn.
The 12v horn relay is connected to the car’s battery, and is activated by the horn button on the steering wheel. When the horn button is pressed, the relay closes and allows current to flow from the battery to the horn.
Wiring Diagram
Here is a wiring diagram for a typical 12v horn relay:
| Terminal | Wire Color | Description |
|---|---|---|
| 85 | Black or Blue | Ground |
| 86 | Red or Yellow | Power from Horn Button |
| 87 | Orange or Brown | Power to Horn |
| 87A | N/A | Not Used |
| 30 | Red or Yellow | Power from Battery |
How to Wire a 12v Horn Relay
To wire a 12v horn relay, you will need:
- A 12v horn relay
- A new horn (if replacing the old one)
- A wire stripper and crimping tool
- A multimeter (optional, for troubleshooting)
Step 1: Disconnect the Battery
Before you begin, make sure the car’s battery is disconnected to prevent electrical shocks or short circuits.
Step 2: Identify the Wires
Using the wiring diagram above, identify each of the five wires that connect to the horn relay:
- 85 – Black or blue wire for ground
- 86 – Red or yellow wire for power from horn button
- 87 – Orange or brown wire for power to horn
- 87A – Not used
- 30 – Red or yellow wire for power from battery
Step 3: Connect the Wires
Using a wire stripper and crimping tool, connect each wire to its corresponding terminal on the horn relay. Be sure to strip each wire’s insulation to the correct length for the crimping connector.
Use a multimeter to test the continuity of each wire to ensure proper connections. Verify that the ground wire (85) has continuity with the car’s chassis or ground point.
Step 4: Test the System
Reconnect the car’s battery and test the horn system by pressing the horn button on the steering wheel. If the horn does not sound, check the wiring connections and fuses, and use a multimeter to troubleshoot any electrical issues.
FAQ
Q: Why do I need a 12v horn relay?
A: A 12v horn relay is necessary to provide a consistent and strong power source to the horn. Without a relay, the horn may not function properly or may drain the car’s battery.
Q: Can I use a different relay for my horn?
A: It is possible to use a different type of relay for your horn, but it is important to choose a relay that can handle the power requirements of your horn system. Consult your car’s manual or a professional mechanic for guidance.
Q: What should I do if my horn still doesn’t work after wiring a new relay?
A: Check the wiring connections, fuses, and the horn itself for any defects or damage. Use a multimeter to test the continuity and voltage of each component. If you are unable to troubleshoot the issue, consult a professional mechanic.
Q: Can I wire a 12v horn relay myself?
A: Yes, it is possible to wire a 12v horn relay yourself. However, it is important to follow safety precautions and consult your car’s manual or a professional mechanic for guidance.
Tips for Troubleshooting
- Check the wiring connections for loose or damaged wires
- Test the fuses to ensure they are not blown
- Check the horn itself for defects or damage
- Use a multimeter to test the continuity and voltage of each component
- Consult your car’s manual or a professional mechanic for guidance
