my dewalt cordless drill trigger feels sticky and sometimes doesn't turn off right away

Diagnosis

The "sticky" sensation and delayed shut-off in the DeWalt DCD771C2 are typically caused by the accumulation of particulate matter—specifically fine sawdust, drywall dust, or metallic shavings—inside the trigger housing. The DCD771C2 utilizes a variable-speed trigger mechanism that relies on a precise spring-return system and a potentiometric switch. When debris enters the gap between the outer plastic trigger shell and the internal switch assembly, it creates mechanical friction that resists the spring's attempt to push the trigger back to the neutral (off) position.

In more severe cases, this "stickiness" is not just mechanical friction but a result of chemical contamination. If the drill was used in an environment with oils, lubricants, or wet cutting agents, these substances mix with dust to create a thick paste. This paste adheres to the trigger pivot points and the internal contact plates, causing the switch to remain partially engaged even after you have released your finger. You can confirm this by removing the battery and manually squeezing the trigger; if it doesn't snap back instantly with a crisp "click," the internal housing is contaminated.

How to Fix It

Follow these steps to deep-clean the trigger mechanism and restore the tactile response of your DCD771C2.

1. Power Isolation: Remove the 20V Max battery pack immediately. Never attempt to clean the trigger area with the battery inserted, as you risk accidentally engaging the motor or shorting the switch.
2. Initial Debris Purge: Use a can of compressed air or a high-pressure air nozzle. Direct the air blast into the gaps around the trigger, focusing on the top and bottom edges where dust typically settles. Pulse the trigger rapidly while spraying to dislodge trapped particles.
3. Chemical Degreasing: If the trigger remains sluggish, use a non-conductive electronic contact cleaner (such as QD Contact Cleaner). Spray the cleaner directly into the trigger assembly. This solvent dissolves the oils and grime that compressed air cannot move.
4. Mechanical Cycling: While the contact cleaner is still wet, squeeze and release the trigger 20 to 30 times in rapid succession. This action works the solvent into the pivot points and helps break up any solidified debris.
5. Final Dry: Use compressed air again to blow out any remaining liquid and loosened grime. Allow the tool to dry completely for 15 minutes before reinserting the battery.
6. Functional Test: Insert the battery and test the trigger at low, medium, and high speeds to ensure there is no "lag" when releasing the switch.

If That Didn't Work

• Trigger Spring Replacement: If the trigger returns slowly but feels "smooth," the internal return spring may have lost its tension or become deformed. This requires a full teardown of the handle housing to replace the spring. If you see a gap where the trigger doesn't sit flush against the housing, the spring is likely the culprit.
• Switch Assembly Swap: If the trigger snaps back physically but the motor continues to run for a second, the internal electronic switch (potentiometer) has failed. You will need to replace the entire trigger switch assembly. Ensure you source the exact OEM part for the DCD771 model to maintain variable speed control.
• Housing Realignment: Check the screws on the clamshell of the drill handle. If the tool was dropped, the plastic housing can warp slightly, pinching the trigger. Loosen the housing screws by a quarter-turn to see if the trigger movement improves; if so, the housing may need to be carefully reshaped or replaced.
• Internal Lubrication: In rare cases of extreme wear, a tiny amount of dry PTFE lubricant can be applied to the external pivot points of the trigger. Avoid using WD-40 or wet greases, as these act as magnets for dust and will make the problem worse within a week.

Heads Up

• Avoid "Feathering" in Dust: Avoid using the trigger at the very lowest speed setting for extended periods in high-dust environments, as this keeps the switch in a position where debris is more likely to wedge.
• No Lubricant in the Switch: Never spray silicone or oil-based lubricants directly into the trigger; this will attract sawdust and create a permanent "sludge" that can permanently ruin the electrical contacts.
• Post-Job Blowout: Make it a habit to blow out your DCD771C2 with compressed air after every major project, especially when working with MDF or drywall, to prevent buildup.
• Battery Safety: Always store your 20V Max batteries in a cool, dry place. Heat can cause the battery casing to expand slightly, which in some rare cases puts pressure on the tool's internal frame.