Troubleshooting Discontinued Fenix FlashlightsUpdated 30 minutes ago

This guide covers troubleshooting for older Fenix flashlights that are no longer sold, from the E, LD, PD, RC, SD, TK, UC, WT, FD and LR series. Start with the checks below, then look up your model for anything specific to it. If you have a current model, see its Manual & Specs article or product page instead.

Start with these checks

Remove the plastic insulation disc. Many rechargeable models ship with a disc inside the body that blocks the battery. Take it out before first use.
Test the battery in another compatible device, or charge it fully or replace it.
Check the battery direction. On most of these flashlights the positive (+) end faces the head (LED end).
Use only one O-ring at each joint. The light comes with its O-rings already installed; the extra one in the box is a spare. An extra O-ring keeps the light from making full contact with the battery.
Lubricate the O-rings with a small amount of silicone grease on a cotton swab.
Tighten the tail cap and head completely.
On lights with an electronic switch, press and hold the switch for about half a second. A quick press won't turn the light on.
On rechargeable lights: if the light only works while plugged in, or the charging indicator stays solid green (or keeps cycling) while plugged in but the light won't run unplugged, the battery likely needs to be replaced.

Model-specific notes

E series

E01: Twist-head activation. Tighten the head completely onto the body to turn the light on.
E02R: Twist-head activation: if the head isn't tightened far enough, the light won't make contact. It uses two O-rings on the body where the head connects and one on the tail cap (all installed from the factory).
E03R (original V1): If the light flashes twice when you press the button, it's in lockout mode; quickly double-press the switch to unlock it. If the charging indicator stays solid green while plugged in but the light doesn't work, the battery may be defective. The indicator should only be lit while charging; if it stays lit when unplugged, that may be a defect. For the E03R V2.0, see its own How to Use, Charge & Troubleshoot article.
E05: Twist-head activation. Screw the head down tightly; it must be fully tightened for the light to come on.
E18R and E25UE: If the light flashes twice when you press the side switch, it's in lockout mode. Double-click the side switch quickly to unlock it.
E28R: Double-click the side switch to exit lockout mode (the light flashes twice when locked). Make sure the head and tail cap are on the correct ends: the tail cap goes where the pocket clip attaches, so the LED faces down when clipped in a pocket. For the E28R V2.0, see its own How to Use, Charge & Troubleshoot article.
E11, E12, E15 and E35UE: No model-specific steps; the checks above apply.

LD series

LD15R: See the rechargeable-battery check above: working only while plugged in usually means the battery needs replacing.
LD32 UVC: Double-click the side switch to exit lockout mode (the light flashes twice when locked). Make sure the head and tail cap are on the correct ends (tail cap where the pocket clip attaches).
LD75C: The rotation ring can get stiff after the light sits unused. It loosens up again once you turn it.
LD09 and LD12: Make sure both the head and tail are fully tightened; otherwise the checks above apply.

PD series

PD32 V2.0: Make sure the head and tail cap are on the correct ends (tail cap where the pocket clip attaches). If it won't work on CR123A batteries, try an 18650; on rare occasions the light doesn't work with CR123As.
PD35 TAC: Make sure the head and tail cap are on the correct ends. If the light turns on but the side switch won't change brightness, it's in Tactical Mode. To switch to Outdoor Mode, turn the light on, press and hold the side switch for 3 seconds, and release when the light blinks twice at low output. Repeat to switch back.
PD36R (original): Make sure the head is fully screwed onto the body. For the PD36R V2, Pro or ACE, see that model's Manual & Specs article.
PD25 (original): Its ARB-L16-700U battery has a built-in micro-USB port: take the battery out and plug a micro-USB cable into the battery itself. No separate charger is needed. (The current PD25R charges through a USB-C port on the light; see its Manual & Specs article.)
PD40R V2.0: If it won't reach full Turbo, charge the battery fully. Turbo steps down automatically as the light heats up and as the battery runs low.

RC series

RC05, RC09 and RC11: If the light flashes twice when you press the side switch, it's in lockout mode; double-click the side switch to unlock it. Make sure the head is fully tightened.
RC15 and RC20: These charge on a cradle. If the light only works on the cradle, or the indicator shows constant green on the cradle but the light won't run off it, the battery may be bad.
RC40: If the light only works while plugged in, or the charging indicator never stops cycling, the battery may be bad. The light's USB power-out function may not work with every device.

TK series

TK11 TAC: Check the tail cap mode selector. On the lock icon, the light won't turn on or off. On Tactical Mode (circle with four arrows), you only get one steady brightness plus strobe; switch to Duty Mode (rectangle with an arrow) for all brightness levels.
TK16 (original V1): If the brightness switch stops working, the light needs service (see below). For the TK16 V2.0, see its Manual & Specs article.
TK20R (original V1): Loosen the tail cap before tightening the tactical ring; a tight tail cap can stop the ring from moving. Once the ring is secure, tighten the tail cap completely. For the TK20R V2.0, see its Manual & Specs article.
TK22 V2.0 and original TK22: Make sure the head and tail cap are on the correct ends: the tail cap goes where the pocket clip attaches, so the LED faces down when clipped in a pocket.
TK22UE: Check the head and tail cap ends as above. If you use the ALF-18 adapter, the 18650's positive (+) end faces the adapter's positive end, and the adapter's positive end faces the head. Charge with a USB-C cable (not micro-USB), and try a different cable and adapter if it won't charge. A red battery indicator means charging; blue means fully charged.
TK35 (all versions): If the charging indicator stays solid green while plugged in but the light doesn't work, the batteries may need replacing.
TK35UE (2018 edition): Make sure the mode selector isn't set to Lockout. If it only runs in Turbo, make sure the selector isn't on Tactical Mode. A solid green charging indicator with a light that won't work means the batteries may need replacing. For the TK35UE V2.0, see its Manual & Specs article.
TK65R: If the light blinks twice when you press a switch, it's locked. Press and hold both switches together for more than 3 seconds to lock or unlock it. If it only works while plugged in, or the indicator keeps cycling, the battery may need replacing.
TK72R: If the switches don't respond, it may be locked. Turn it off and double-press the third switch (marked "F") to lock or unlock it. If it only works plugged in or the indicator keeps cycling, the battery may need replacing. USB power-out may not work with every device.
TK09, TK15UE (and the older TK15), TK25 (all versions), TK32, TK47, TK47UE and TK75 (2018 and earlier): No model-specific steps; the checks above apply.

UC series

UC01: If the charging indicator stays solid green while plugged in but the light won't work, the battery may need replacing.
UC02: Same battery check as the UC01. It uses two O-rings on the body where the head connects and one on the tail cap.
UC30 (all versions): Make sure the tail cap is screwed on all the way. A solid green indicator with a light that won't work means the battery may be bad. If the side switch falls off, the light needs warranty service (see below).
UC40UE: No model-specific steps; the checks above apply.

Other models

LR40R (original V1): If it only works plugged in, or the indicator never stops cycling, the battery may be bad. USB power-out may not work with every device. The LR40R V2.0 is different: its battery is built in and there's no tail cap; press and hold the electronic switch for half a second, or turn the toggle switch to any mode if it's locked.
WT20R: Make sure the battery compartment is fully and tightly closed.
WT50R: Make sure the two body sections are tightened completely together. If it only works plugged in, or the indicator keeps cycling, the battery may need replacing. USB power-out may not work with every device.
SD11 and SD20 dive lights: No model-specific steps; the checks above apply. Keep the O-rings clean and lightly greased.
FD20 and FD41: No model-specific steps; the checks above apply.

Still not working?

Keep your proof of purchase and contact Fenix Store support through live chat (the chat button on any page of fenix-store.com) or at [email protected] for warranty service. See our Warranty and Repair page for details.

For more general tips, see our Flashlight Troubleshooting Guide.

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