the led worklight on my 2953 stays on all the time, even with the trigger released and battery removed

Diagnosis

The primary cause of the LED worklight remaining illuminated on the Milwaukee M18 Fuel 2953-20 is a catastrophic failure of the power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) on the main PCB. In this specific circuit, the MOSFET acts as a high-speed electronic switch that opens and closes based on signals from the tool's logic controller. When this component fails, it typically "fails short," meaning it creates a permanent conductive path between the power rail and the LED assembly. Because the MOSFET is stuck in a closed position, the LED is receiving power regardless of the trigger state. The reason the light remains on even after the battery is removed is due to the large electrolytic capacitors located on the control board. These capacitors store a residual electrical charge that slowly leaks into the LED; since the "gate" is permanently open, the light will stay lit until the capacitors are fully drained. If the light returns immediately upon sliding a battery back in without pulling the trigger, the MOSFET is definitively blown.

How to Fix It

Since the 2953-20 is a sealed unit with an integrated electronics module, replacing a single MOSFET requires precision soldering and board-level diagnostics. For most users, the only reliable fix is replacing the main control assembly.

1. Remove the M18 battery pack and set the tool on a stable work surface.
2. Using a T15 Torx driver, remove the housing screws located on the side of the tool casing. Be careful not to strip the heads, as the plastic housing can flex.
3. Carefully pry the two halves of the clamshell casing apart. Use a plastic trim tool to avoid gouging the housing.
4. Locate the main PCB (Printed Circuit Board) situated behind the trigger assembly.
5. Disconnect the wiring harness leading from the motor and the trigger switch to the board.
6. Remove the mounting screws securing the PCB to the chassis.
7. Inspect the board for "magic smoke" marks or charred components near the LED circuitry. If you are skilled in SMD soldering, you can desolder the failed MOSFET and replace it with an equivalent N-channel MOSFET rated for the same voltage and current.
8. If you are not an electronics technician, replace the entire control board assembly (Part No. 4932-XXX series depending on the specific manufacturing run).
9. Reassemble the housing, ensuring no wires are pinched between the clamshell halves, and tighten the T15 screws firmly but do not over-torque.

If That Didn't Work

• Check for Trigger Sticking: Inspect the trigger assembly for debris or melted plastic that might be holding the internal micro-switch in the "engaged" position. If the trigger feels "mushy" or doesn't snap back fully, the mechanical switch may be failing, sending a constant "ON" signal to the board.
• Inspect for Water Ingress: If the tool was used in rain or a damp environment, check the PCB for corrosion or mineral deposits (white crust). Use 99% Isopropyl Alcohol and a soft toothbrush to clean the board. A conductive bridge of corrosion can bypass the MOSFET and trigger the LED.
• Test with a Different Battery: While rare, a malfunctioning battery with a faulty protection circuit can occasionally cause erratic behavior in the tool's logic. Swap to a known-good M18 High Output battery to rule out voltage spikes from a failing cell.
• Check the LED Wiring Harness: Inspect the thin wires leading from the board to the LED. If the insulation has rubbed through and the wire is shorting directly to a power rail, the light will bypass the control board entirely.

Heads Up

• Capacitor Discharge: Even with the battery removed, the board holds a charge. Avoid touching the PCB components with metal tools to prevent accidental shorts.
• Warranty Warning: Opening the tool housing and removing screws from the PCB will void the Milwaukee manufacturer warranty. Check your warranty status before disassembly.
• Dust Management: When the case is open, use compressed air to blow out the motor housing. Accumulated drywall or construction dust can cause overheating, which is often what kills the MOSFETs in the first place.
• ESD Safety: Always use an anti-static wrist strap when handling the control board to prevent electrostatic discharge from frying the logic chip.