my milwaukee m18 drill driver won't go into reverse, the switch is stuck.

Diagnosis

The forward/reverse selector switch on the Milwaukee M18 2801-20 is a mechanical slider that interacts with the motor's polarity and the trigger mechanism. If the switch is stuck, it is typically caused by "site debris"—fine sawdust, drywall dust, or metal shavings—that has migrated into the switch housing, creating friction. In more severe cases, the internal plastic detent or the spring-loaded locking mechanism has snapped or shifted out of alignment, preventing the slider from moving into the reverse position.

How to Fix It

1. Power Down: Remove the M18 battery pack immediately to ensure the tool cannot be accidentally triggered during cleaning.
2. Surface Debris Removal: Use a can of compressed air or a high-pressure air nozzle to blow out the gaps around the selector switch. Aim the air directly into the seams of the slider to dislodge packed debris.
3. Chemical Cleaning: Apply a small amount of non-conductive electrical contact cleaner or a fast-evaporating degreaser to the edges of the switch. While the fluid is wet, gently wiggle the switch back and forth to break up any solidified grime.
4. Mechanical Reset: If the switch feels "spongy," ensure the tool is not stuck in the center (neutral/lock) position. Firmly but carefully push the switch toward the reverse icon.
5. Dry and Test: Wipe away any excess residue with a lint-free cloth and reinsert the battery to test the functionality.

If That Didn't Work

If the switch remains frozen or moves without engaging the motor, the internal plastic cam or the return spring has likely failed. Because the selector is integrated into the trigger assembly, you will need to disassemble the tool housing to inspect the internal switch gear. If you find a broken plastic tab, the entire trigger/switch assembly must be replaced as a single unit. Avoid using WD-40 or heavy lubricants, as these attract more dust and can gum up the electrical contacts over time.

Heads Up

Never force the selector switch with pliers or a screwdriver. Forcing a jammed switch can snap the internal plastic detents, turning a simple cleaning job into a full component replacement. Remember that the drill will not operate if the switch is even slightly off-center.