Quick answer
- Press the nose firmly into the work before you pull the trigger. Half-pressing the work-contact safety is the number one reason these "won't fire."
- The dry-fire lockout stops the tool when nails run low. Load a fresh strip before you assume anything is broken.
- Check the trigger lock-off switch. It is easy to bump into the locked position.
- If the driver stalled, cycle the stall release lever on the front left of the motor housing to reset the blade.
How these actually fire
A quick note on the mechanism, because it explains half the "problems." The 20V MAX XR nailers, the DCN680 18-gauge brad gun, the DCN650 and DCN660 finish guns, and the DCN692 framer, use a brushless flywheel motor instead of gas or air. You have to press the nose firmly and squarely into the work so the work-contact safety fully depresses, then pull the trigger. Feathering the trigger or holding the gun at an angle is the most common reason a perfectly good nailer sits there doing nothing.
Dry-fire lockout
DeWalt builds in a dry-fire lockout that stops the tool firing when the magazine runs low, around the last few fasteners. It is there so you do not drive blanks and dent your trim, but it feels exactly like a dead tool. Load a fresh strip and try again before you go any further. While the magazine is open, confirm you are running the right fasteners. The DCN680 wants 18-gauge brads, and 16-gauge finish nails will not feed through it.
Trigger lock and depth setting
Look at the trigger lock-off. There is a switch that disables the trigger so the gun cannot fire in your bag, and a thumb catches it into the locked position more often than you would think. Flip it back to the fire side.
Then check the depth-of-drive wheel. Backed all the way out, the work-contact tip may not travel far enough to arm the tool against thinner stock. Dial it toward the middle, then press the nose in hard and flat. A nailer held at an angle frequently will not let the contact tip complete its stroke, so the tool reads it as "not pressed."
Clear a stall or a jam
If the driver blade stalled partway through a drive, the tool locks up to protect itself. DeWalt put a tool-free stall release lever on the front left of the motor housing for exactly this. Cycle that lever to return the driver blade to its home position. On the DCN680 the diagnostic LEDs help: the right-hand LED flashing continuously points to a jam. Release the no-mar tip and the magazine latch, pull any bent fastener out with needle-nose pliers, then work the stall release and reload. Do not pull the trigger again until the jammed nail is physically out, or you will bend another one against it.
Then the battery
A nailer draws a hard, instant load to spin that flywheel, so a pack that still runs a drill fine can fall short here. Swap in a different fully charged 20V MAX battery before you blame the tool. Press the fuel gauge. If it reads low or will not hold a full charge off the charger, the cells are tired.
Mind the cold, too. Lithium-ion will not charge below roughly 32°F (0°C), and that is a normal safety interlock, not a defect. A pack that sat in a cold truck overnight may simply need to reach room temperature before it will run. Seat the battery until it clicks, since a pack a hair loose reads as completely dead.
When it is actually broken
If a fresh battery, a loaded magazine, the trigger lock off, and a cycled stall release still get you nothing, the failure is inside, usually the flywheel motor or the control electronics. The tell is a motor that will not spin up at all with a known-good pack and the nose pressed fully home. That is a service-center job, not a driveway fix. DeWalt's warranty runs three years on these tools, so check your purchase date first. A tool still under warranty often gets repaired or swapped rather than charged for.
Most of the time, though, it is the lockout or the trigger lock. Load nails, switch the trigger lock off, press the nose in hard, and the gun goes back to work.