What are the basic tasks I can perform to keep my light operating?
Follow these steps to troubleshoot:
1. Remove the tailcap
2. Look on the inside of the tailcap and you may see a silver o-ring with two little indentions in it.
3. Take a spanner wrench or needle-nose pliers and place the tips in the little indentions in the silver o-ring in the tailcap.
4. Turn COUNTER CLOCKWISE. If the ring is loose any, that can cause your light to not work properly.
5. IMPORTANT: Do not put Loctite glue (or such) on the o-ring. To replace the switch in the tailcap, you have to be able to removed this ring to access the switch.
6. It's a good idea to periodically check to make sure it is secure. With the clicking on and off of your light, that ring can work loose.
NOTE: NOT ALL FENIX FLASHLIGHTS HAVE THE SILVER O-RING AS IN THE PHOTO. FOLLOW THE ABOVE STEPS IF YOUR LIGHT HAS THE TYPE OF O-RING IN THE PHOTO BELOW.
General Maintenance Tips
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 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 boot for your tail cap. Replacement boots are useful for changing the color of adding a glow-in-the-dark flair to your tail-cap. The video below shows the process in detail: