Quick answer
- Most often it's the battery, not the tool. Swap in a different charged 20V MAX pack before anything else.
- Clean the battery contacts and the rails inside the tool. Grit and corrosion there mimic a dead driver.
- Check the forward/reverse collar isn't stuck in the center position, which locks the trigger on purpose.
- If the tool quit under heavy load, let the tool and pack cool. The battery's protection circuit can shut it off, and a pack may need recharging before it works again.
Symptoms and what they point to
A DeWalt impact driver "not working" shows up a few different ways, and each points somewhere. Dead silence with a full battery can mean a contact or trigger problem. A tool that runs then fades under load points at a tired or overheated battery. Clicking with no rotation can be the forward/reverse control or a bit-retention issue, not the motor. Knowing which symptom you've got saves you tearing into the wrong thing.
One myth to kill first: the DCF887 and the other XR impact drivers are brushless. There are no motor brushes to wear out or replace, so any advice telling you to swap brushes on these is for an older brushed tool, not yours.
Start with the battery
This is the fix most of the time, so do it properly.
- Try a known-good pack. Put a different fully charged 20V MAX battery in the tool. If it runs, your original pack is the problem, not the driver.
- Check the pack's fuel gauge. Press the button on the battery. If the lights are dim or it won't show a full charge after a long sit on the charger, the cells are tired.
- Mind the temperature. A charger won't charge a pack that's too cold or too hot; DeWalt's charger instructions say not to charge below 40°F (4.5°C) or above 104°F (40°C). That's a normal safety interlock, not a fault. A battery left in a cold truck may simply need to warm to room temperature before it'll charge or run.
- Seat it fully. Push until it clicks firmly. A pack that's a hair loose can read as completely dead.
Then the contacts and trigger
If a fresh battery doesn't fix it, look at the connection between pack and tool. Pop the battery off and inspect the terminals on both the pack and the rails inside the tool. Sawdust, drywall grit, and corrosion build up there and break the circuit. Blow it out with compressed air and gently clean the contacts. Don't bend the terminals.
The trigger switch is the next suspect. If the tool works intermittently, cuts out when you ease off, or only runs at full speed, the variable-speed switch may be worn. A failed switch is a service item, and at that point many people weigh the repair against the tool's age.
The thing people miss
Check the forward/reverse control. The center position of that button above the trigger locks the tool off so it can't fire by accident in your bag. If it's parked halfway, the driver is dead by design. Click it fully to forward or reverse and try again. It sounds too obvious to mention, and it's caught plenty of people who were about to send a perfectly good tool in for service.
If the tool quit mid-job and got hot, set it down and let the tool and battery cool. The battery's electronic protection can shut the tool off under heavy load, and the pack may need to be recharged before it runs again.
When it's actually broken
If a known-good battery, clean contacts, and a confirmed-forward collar still get you nothing, the failure is inside the tool, usually the switch or the electronic control. DeWalt's warranty runs three years on these, so check your purchase date before you open it up. A tool under warranty may be repaired or replaced, so start with DeWalt support before you order parts.