How to manually wire Fast Fit wiring harness to high beam

How to manually wire Fast Fit wiring harness to high beam

Wiring Your Fast Fit Harness (Single or Dual) to Non-Standard High Beam Sockets

This guide helps you manually wire your Fast Fit harness, whether it's the Fast Fit Single Harness or the Fast Fit Dual Harness, to high beams not covered by the included adaptors. Remember, professional help is always recommended if unsure.

Before you begin:

    • Ensure you have the correct Fast Fit harness model and tools (wire strippers, multimeter, soldering iron, heat shrink/tape).
    • Safety first! Improper wiring can damage your vehicle or cause injury.


    1. Expose Harness Wires: Remove the input socket connector on your Fast Fit harness to reveal the wires. Strip 2-4cm of insulation from each wire, maintaining enough black insulation for handling.

    1. Identify High Beam Wires:

        • Locate your vehicle's high beam bulb.
        • Do not cut wires! Identify positive and negative wires (if marked) or use these methods: A. Voltage check: * Multimeter on DC voltage mode. * Touch probes to exposed high beam wires. * Activate high beams. * Positive wire shows +12V, negative shows -12V (swap probes if needed). * Caution: Avoid short circuits! B. Continuity test: * Multimeter on continuity mode. * Touch one probe to a high beam wire, the other to a car ground. * Beep indicates negative wire.
    1. Connecting the Wires:

        • Match and connect the Fast Fit harness wires to your vehicle's high beam wires (positive to positive, negative to negative).
        • Solder the connections securely.
        • Apply heat shrink or electrical tape for insulation and protection.
    1. Dust Cap and Final Touches:

        • You may need to modify the dust cap for wiring access. Leave slack for easy removal.
        • Seal any drilled holes or slits properly.

Additional Tips:

    • Purchase vehicle-specific adaptors for a simpler solution.
    • Double-check connections before activation.
    • Securely mount the control box and relay (if applicable).
    • Refer to the specific manual for your Fast Fit Single Harness or Fast Fit Dual Harness for additional details.

Remember: Safety is paramount. If unsure, consult a qualified electrician or mechanic.

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