How to wire 12v automotive relay with positive trigger

Introduction

This tutorial will guide you through the process of wiring a 12V automotive relay with a positive trigger. Wiring may seem intimidating, but it's a straightforward task once you understand the components involved. A relay acts as a switch that controls a larger power source, and in this tutorial, we will focus on the battery side and the coil side, making it simple for automotive applications.

Step 1: Gather Your Materials

Before you begin wiring the relay, ensure you have the following materials:

• 12V automotive relay
• Wire (appropriate gauge for your application)
• Connectors (spade, ring, or solder)
• Electrical tape or heat shrink tubing
• A multimeter (for testing)
• A fuse (to protect your circuit)

Step 2: Understand the Relay Connections

Familiarize yourself with the relay's pin configuration. Typically, a standard automotive relay has five terminals:

• 30: Power input from the battery
• 87: Power output to the device you want to control
• 86: Positive trigger input (coil side)
• 85: Ground (coil side)
• 87a: Normally closed output (optional, not used in positive trigger setups)

Step 3: Connect the Power Side

1. Connect Terminal 30:

   • Run a wire from the positive terminal of the battery to terminal 30 on the relay.
   • Use a fuse inline with this connection to protect against shorts.

2. Connect Terminal 87:

   • Connect a wire from terminal 87 to the device you want to control (e.g., lights, fans).
   • Ensure the device is rated for 12V.

Step 4: Connect the Coil Side

1. Connect Terminal 86:

   • Connect a wire from terminal 86 to the positive trigger source (this could be a switch or another 12V source).

2. Connect Terminal 85:

   • Connect terminal 85 to a good ground. This can be the negative terminal of the battery or a suitable grounding point on the vehicle.

Step 5: Test Your Connections

1. Use a Multimeter:

   • Before powering the circuit, check all connections with a multimeter to ensure there are no shorts.

2. Activate the Relay:

   • With the trigger source activated (e.g., turning on the switch), check if the device connected to terminal 87 powers on.

Conclusion

Wiring a 12V automotive relay with a positive trigger is a simple yet effective way to control high-power devices in your vehicle. By following these steps, you can safely and efficiently set up your relay system. Always remember to use fuses for protection and double-check your connections to avoid issues. If you're interested in learning about ground trigger relays, stay tuned for our upcoming video!