After viewing the video and trying the steps below, please check out our Knowledge base Page for a complete list of troubleshooting steps for your specific flashlight.
Diagnose Your Switch
If your light is clean and has fresh batteries, but still does not work, you should diagnose your switch. To do this, remove the tail cap (if the light uses a tail switch) and ensure the batteries are installed correctly. Next, place a metallic object like a paperclip, some tweezers, or a screwdriver across the tail section so that it makes contact with both the flashlight and the battery. If the light turns on, you know the issue is with the switch. If it does not turn on, the issue is with the LED or the circuitry surrounding it.
If the issue is with your switch (If the light turns on when the metal object is laid across the tail) then you can take a closer look at the switch assembly. Inspect the switch and ensure there is nothing loose inside. If it does seem loose, use a tool to twist the retaining ring counter-clockwise. This will ensure everything is tightly in place. Re-attach the tailcap and see if tightening the switch solved the issue.
If all of this fails, you can resort to your flashlight's warranty. Most problems with LED flashlights have to do with the issues discussed above.
As a final tip, you can take apart the switch assembly. This is also useful if you have a new rubber boot (switch cover) for your tail cap. Replacement boots are useful for changing the color or adding a glow-in-the-dark flair to your tail-cap. The video below shows the process in detail:
For model specific troubleshooting click here