Symptoms
- Trigger does nothing when pulled
- No sound, no motion at all
- Saw worked fine last use
- LED indicator (if present) is off
Likely causes
- CommonBattery dead or not seated (cordless models)A partially inserted or drained battery won't power the tool.
- CommonSafety lock-off switch not disengagedMost saws require pressing a lock button before the trigger works.
- CommonCord, outlet, or extension cord issue (corded models)A dead outlet or damaged cord cuts power before it reaches the saw.
- PossibleWorn carbon brushesBrushed motors stop working once brushes wear down too far.
- Less commonInternal switch failureThe trigger switch itself can fail after years of use.
What to do
- For cordless saws, remove the battery, check its charge level, and try a known-good charged battery if you have one.
- Confirm the safety lock-off button is fully pressed before pulling the trigger.
- For corded saws, test the outlet with another device and check the cord for cuts or looseness at the plug.
- Try a different extension cord, since underrated or damaged cords can prevent enough power from reaching the saw.
- If comfortable, remove the brush caps (if accessible) and check whether the carbon brushes are worn down to nubs.
- If none of the above works, stop using the saw and have it inspected rather than opening the motor housing.
Tools and parts
- Charged battery (cordless) or tested outlet (corded)
- Multimeter (optional)
- Screwdriver
Replacement battery packSearch: “cordless circular saw battery replacement”
Carbon brush setSearch: “circular saw carbon brushes replacement”
When to call a pro
If the battery, cord, and lock switch all check out and the saw still won't run, a tool repair shop should test the motor and internal switch.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.