InstallationDecember 28, 202510 min read

Complete Guide to Auxbeam Wiring Harness Installation

A step-by-step installation guide for Auxbeam's heavy-duty wiring harness. Learn how to properly wire your LED lights for optimal performance and safety.

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Complete Guide to Auxbeam Wiring Harness Installation

A quality LED light setup is only as good as its wiring. The Auxbeam heavy-duty wiring harness provides everything you need for a safe, professional installation. This guide walks you through the complete process.

What's in the Box

The Auxbeam wiring harness kit includes:

  • 40A relay with mounting bracket

  • 40A inline fuse with holder

  • LED rocker switch (various styles available)

  • DT connectors for light bar connection

  • 16AWG primary wiring (approximately 10 feet)

  • Ring terminals for battery connection

  • Zip ties and mounting hardware

    • Tools You'll Need

    Before starting, gather these tools:

  • Socket set and wrenches

  • Wire strippers and crimpers

  • Electrical tape or heat shrink

  • Drill with bits (for switch mounting)

  • Multimeter (for testing)

  • Zip tie gun (optional but helpful)

    • Step-by-Step Installation

    #### Step 1: Plan Your Route

    Before running any wires, plan the routing:

  • Identify where the relay will mount (firewall or fender well)

  • Plan the switch location (dash panel or auxiliary switch spot)

  • Trace the path from battery to relay to lights

  • Look for existing grommets to pass wires through firewall

    • Pro Tip: Take photos of your planned route to reference during installation.

    #### Step 2: Mount the Relay

    The relay should be:

  • Close to the battery (within 18 inches ideal)

  • Protected from water but accessible

  • Securely mounted to prevent vibration damage

    • Common mounting locations:

  • Inner fender well

  • Firewall (engine side)

  • Near the battery tray

    • Use the included bracket or a universal relay mount for a secure installation.

    #### Step 3: Connect Battery Power

    Important: Disconnect the negative battery terminal before starting electrical work.

  • Route the red power wire from relay to battery positive

  • Connect the inline fuse holder within 6 inches of the battery

  • Use the ring terminal to connect to the positive post

  • Ensure the connection is tight and corrosion-free

    • #### Step 4: Ground Connection

    The black ground wire needs a solid chassis ground:

  • Find a bare metal location on the frame or firewall

  • Sand away any paint or coating for good contact

  • Use a ring terminal and bolt/screw to secure

  • Verify ground connection with multimeter (should read near 0 ohms)

    • #### Step 5: Run Switch Wiring

    The switch control wire runs from the relay to your chosen switch location:

  • Route through an existing firewall grommet if possible

  • If drilling, use a rubber grommet to protect the wire

  • Leave enough slack for switch installation

  • Keep wiring away from heat sources and moving parts

    • #### Step 6: Install the Switch

    The LED rocker switch requires:

  • A rectangular cutout (size varies by switch style)

  • Drill pilot holes at corners

  • Cut between holes with a rotary tool or nibbler

  • Test fit and adjust as needed

  • Snap switch into place

    • For auxiliary switch panel installations (common in Jeeps and trucks), the process is simpler—just pop out the blank and insert the switch.

    #### Step 7: Connect the Light Bar

    The DT connector makes this simple:

  • Route harness wiring to light bar location

  • Connect DT plug to light bar connector

  • Secure excess wiring with zip ties

  • Ensure connector is seated fully

    • #### Step 8: Test the System

    Before buttoning everything up:

  • Reconnect battery negative terminal

  • Turn on switch—lights should illuminate

  • Verify relay clicks when switch activates

  • Check all connections for heat after 5 minutes of operation

  • Test waterproof connections with spray if concerned

    • Troubleshooting Common Issues

    Lights don't turn on:

  • Check fuse (most common issue)

  • Verify ground connection

  • Test switch with multimeter

  • Check DT connector is fully seated

    • Relay clicks but no light:

  • Check fuse again

  • Verify power at light connector

  • Test light bar directly with jumper wires

    • Intermittent operation:

  • Look for loose connections

  • Check for corroded terminals

  • Verify ground is solid

    • Wiring Best Practices

  • Use heat shrink over electrical tape when possible

  • Secure all wiring every 12-18 inches

  • Keep wiring away from exhaust and moving parts

  • Use split loom in exposed areas

  • Label wires for future troubleshooting

    • Upgrading for Multiple Lights

    Running multiple light bars or pods? Consider:

  • Using a larger relay (60A or 80A)

  • Adding a second fuse for redundancy

  • Installing a fuse block for cleaner organization

  • Upgrading to 12AWG primary wire for longer runs

    • Final Thoughts

    A proper wiring installation takes time, but the results are worth it. Your lights will perform reliably for years, and you'll have the confidence of knowing the installation was done right.

    The Auxbeam wiring harness provides quality components at a reasonable price. Combined with careful installation, you'll have a setup that rivals professional installations costing much more.

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