Repair intermittent switch on dewalt 20 Volt impact driver

Unfortunately Dewalt switches are solid state, meaning there is little to nothing you can do to fix them when they don't work. Occasionally spraying them with electronics cleaner and blowing them out with clean, dry air will make them work a little longer but more often than not you simply have to replace the switch. The part number for your driver is N084669. They cost between $65 and $75 so shop around or check with a local repair center.