Quick answer

Ensure both the strobe and FJ-X3 M trigger are on the same channel and ID code; if they still don't fire, reset the trigger pairing before troubleshooting cables or distance.

Why pairing drops on location

When you're moving lights between stands, packing them in the Westcott FJ400 II 2-Light Backpack Kit, or shooting in a new environment, the trigger can lose sync due to accidental button presses, battery changes, or radio interference from other gear. The FJ-X3 M trigger uses a digital ID code system, not just a channel number, so resetting that pairing is often the fix.

Diagnosis steps

  • Symptom: Strobe does not fire when shutter is pressed, or fires intermittently. No error code on the FJ400 II screen.
  • Likely cause: Trigger and strobe are not set to the same channel and ID code. The FJ-X3 M trigger supports 32 channels and multiple ID codes to avoid interference. A recent battery swap or accidental touch can change them.
  • Corrective action – Reset pairing: On the FJ400 II strobe: press the Menu button, go to Trigger Settings, set Channel and ID to match the same numbers you choose on the trigger. On the FJ-X3 M trigger: press and hold the ID button for 3 seconds to enter pairing mode, then select the matching ID code. The strobe should fire a test flash to confirm. If the test flash works, the issue is resolved. If not, continue.
  • Still not working?: Check the sync cable connection if using a radio receiver, or move the trigger closer to the strobe (within 30 feet). Try a fresh set of batteries in the trigger. If nothing helps, reset the strobe to factory defaults under Menu > Reset Settings, then repeat the pairing process.

Product reference

  • WESTCOTT FJ400 II 2-Light Backpack Kit with FJ-X3 M Universal Trigger: The Westcott FJ400 II Touchscreen Strobe redefines portable lighting with unmatched speed, reliability, and color accuracy. That reliability depends on a solid trigger connection, which you can restore quickly with the steps below.

    WESTCOTT FJ400 II 2-Light Backpack Kit with FJ-X3 M Universal Trigger

    WESTCOTT FJ400 II 2-Light Backpack Kit with FJ-X3 M Universal Trigger