4 Pin Relay Wiring Diagram Driving Lights

Auxiliary driving lights significantly enhance visibility in low-light conditions, making night driving safer and more comfortable. However, directly connecting these lights to your vehicle’s electrical system can overload circuits and potentially damage sensitive components. A 4 pin relay offers a safe and reliable solution by acting as an electrical switch, allowing a low-current circuit to control a high-current circuit for your driving lights. Understanding the 4 pin relay wiring diagram is crucial for a successful and safe installation.

Benefits of Using a 4 Pin Relay for Driving Lights

Employing a 4 pin relay when wiring driving lights offers several key advantages:

• Safety: Prevents overloading existing circuits, protecting your vehicle’s electrical system.
• Reliability: Ensures the driving lights receive sufficient power without voltage drops.
• Controlled Activation: Allows for controlled switching of the driving lights, often through an existing high beam circuit or a dedicated switch.
• Longevity: Reduces stress on switches and wiring, extending the lifespan of components.

Understanding the 4 Pin Relay Wiring Diagram

A typical 4 pin relay consists of four terminals, each serving a specific function. The following diagram and explanation will clarify their roles:

Terminal 30: This is the common terminal and is connected directly to the positive (+) terminal of the battery, typically through a fused link. This provides the high-current power source for the driving lights. Discover more free resources across our collection library.

Terminal 87: This is the output terminal. It connects to the positive (+) terminal of your driving lights. When the relay is energized, terminal 30 and terminal 87 are connected, allowing power to flow to the lights.

Terminal 85: This is one side of the relay coil and is connected to ground (-). This completes the coil circuit.

Terminal 86: This is the other side of the relay coil and is connected to the trigger source, such as the high beam circuit or a dedicated switch. When voltage is applied to this terminal, the relay is energized.

Therefore, the sequence of installing the 4 pin relay wiring diagram driving lights is as follows:

1. Connect terminal 30 to the positive terminal of the battery (with a fuse).
2. Connect terminal 87 to the positive terminal of the driving lights.
3. Connect terminal 85 to ground.
4. Connect terminal 86 to the trigger source (high beam or switch).
5. Connect the negative terminal of the driving lights to ground.

Practical Application

Here’s a step-by-step guide to wiring your driving lights using a 4 pin relay, expanding on the diagram understanding:

1. Gather Materials: You’ll need a 4 pin relay, wiring (appropriate gauge for the current), a fuse holder and fuse (matched to the driving light’s amperage), wire connectors, a wire stripper, and a crimping tool.
2. Mount the Relay: Choose a location near the battery and away from heat and moisture. Secure the relay properly.
3. Battery Connection (Terminal 30): Connect a wire from the positive terminal of the battery to terminal 30 on the relay. Important: Insert a fuse holder in this wire, as close to the battery as possible, and install the appropriate fuse.
4. Driving Lights Connection (Terminal 87): Run a wire from terminal 87 on the relay to the positive terminal of your driving lights.
5. Ground Connection (Terminal 85): Connect terminal 85 on the relay to a reliable ground point on the vehicle’s chassis. Ensure a clean metal-to-metal contact.
6. Trigger Source Connection (Terminal 86): Choose your trigger source. You can tap into the high beam wire (ensure it’s the positive wire) or install a dedicated switch inside the vehicle. Connect this wire to terminal 86 on the relay.
7. Driving Lights Ground: Connect the negative terminal of the driving lights to a reliable ground point on the vehicle.
8. Test: Once all connections are secure, test the driving lights by activating your chosen trigger (high beams or dedicated switch).

1. Troubleshooting / Common Issues

• Driving lights don’t turn on: Check the fuse, relay connections, ground connections, and the trigger source. Use a multimeter to verify voltage at each point.
• Driving lights turn on without the trigger: The relay may be faulty (contacts stuck). Replace the relay.
• Driving lights are dim: Check for voltage drops due to undersized wiring or poor connections.

2. Tips / Best Practices

• Use quality wiring and connectors: This ensures reliable connections and prevents corrosion.
• Properly crimp all connections: A loose connection can cause voltage drops and heat buildup.
• Protect wiring with loom or conduit: This protects the wires from damage and wear.
• Choose the correct fuse size: A fuse that is too large will not protect the circuit; a fuse that is too small will blow frequently.

FAQs

Q: What size fuse should I use?

A: The fuse size should be slightly higher than the total amperage draw of your driving lights. Check the light’s specifications. As a general rule, a 15A or 20A fuse is sufficient for most driving light setups.

Q: Can I use a 5 pin relay instead of a 4 pin relay?

A: Yes, a 5 pin relay can be used. The 5th pin (87a) is normally closed, meaning it provides a connection when the relay is not energized. Simply ignore the 87a terminal if it’s not needed.

Q: Can I connect multiple driving lights to a single relay?

A: Yes, but ensure the relay and wiring are rated to handle the combined current draw of all the lights. Exceeding the relay’s capacity can damage it or create a fire hazard.

Q: Where can I find a reliable 4 pin relay wiring diagram?

A: Online searches provide various diagrams, but prioritize reputable sources like automotive forums, manufacturer websites, and wiring diagram databases. Always double-check the diagram against your specific relay’s pin markings.

Conclusion

Mastering the 4 pin relay wiring diagram for driving lights is essential for a safe, reliable, and effective installation. By understanding the function of each terminal and following a proper wiring procedure, you can confidently enhance your vehicle’s lighting system while protecting its electrical components. Always prioritize safety and consult a qualified professional if you’re unsure about any aspect of the wiring process. Incorrect wiring can lead to damage or fire, highlighting the importance of meticulous attention to detail and a thorough understanding of the 4 pin relay wiring diagram driving lights connection method.