my greenworks 40v lawn mower won't start, just makes a clicking sound when i pull the handle, what's wrong?

Diagnosis

The clicking sound you hear when pulling the safety handle is the sound of the starter solenoid or the internal relay attempting to engage the motor, but failing to sustain the current required to spin the blade. This typically indicates a "voltage drop" scenario. The battery has enough surface charge to trigger the relay (the click), but not enough amperage to overcome the initial resistance of the motor, or there is a physical interruption in the electrical circuit preventing full power delivery. This is most commonly caused by oxidized battery terminals, a slightly loose battery seating, or a failing cell within the 40V lithium-ion pack. In some cases, the clicking is actually the safety interlock switch failing to fully close, meaning the mower thinks the handle isn't fully depressed, causing the circuit to rapidly open and close. You can confirm this by checking if the LED indicator on the battery flashes rapidly when you pull the handle; if it does, the battery is dropping voltage under load and is likely the culprit.

How to Fix It

To resolve the clicking and restore power to the motor, follow these precise steps to ensure a clean electrical connection and proper safety engagement:

1. Power down the unit completely and remove the 40V battery pack by pressing the release button firmly and sliding the pack out of the housing.
2. Inspect the metal contact terminals on both the battery and the mower's docking port. Use a clean, dry microfiber cloth or a cotton swab dipped in 90% isopropyl alcohol to wipe away any grass clippings, dust, or oxidation from the gold-plated pins.
3. Check the battery terminals for any signs of bending or recession. Ensure the pins are flush and not pushed back into the plastic casing.
4. Slide the battery back into the slot, applying firm pressure until you hear a distinct, audible "click" from the locking tabs. A loose fit of even 1-2 millimeters can cause the clicking sound due to high resistance.
5. Ensure the mower handle is fully unfolded and the locking knobs are tightened securely. If the handle is slightly skewed, the safety bail may not be compressing the internal switch fully.
6. Grip the safety handle (bail) and pull it firmly against the main handle. Ensure there is no debris trapped between the bail and the handle that could prevent a full 100% compression of the switch.

If That Didn't Work

• Perform a Hard Battery Reset: Remove the battery and hold the start handle down for 30 seconds to drain any residual capacitance from the control board. Reinsert a fully charged battery and try again.
• Test with a Secondary Battery: If you own a second 40V Greenworks battery (such as one from a blower or trimmer), insert it. If the mower starts immediately, the original battery has a failed internal cell and can no longer provide the necessary "cranking" amps, even if it shows a full charge on the LED display.
• Inspect the Safety Switch Spring: Remove the plastic shroud around the handle area to inspect the spring-loaded safety switch. If the spring has snapped or shifted, the switch will "flutter" when pulled, creating a rapid clicking sound. You may need to manually reposition the spring to ensure the switch is fully depressed.
• Check for Blade Obstructions: Tip the mower on its side (battery removed!) and check for thick clumps of wet grass or a foreign object jammed in the blade. If the motor is physically seized, the relay will click but the motor won't turn to prevent a total electrical blowout.

Heads Up

• Never store your 40V batteries in temperatures below 32°F (0°C) or above 100°F (38°C), as this permanently damages the cell chemistry and leads to the voltage drop issues described above.
• Avoid letting the battery drain to 0%. Recharge the pack once it hits the last bar to extend the overall lifespan of the lithium cells.
• Always clean the underside of the deck after every use; accumulated grass buildup increases the load on the motor, which puts more strain on the battery and the starter relay.
• When inserting the battery, avoid "slamming" it into the port; a firm, steady push ensures the terminals align without damaging the plastic guide rails.