The handle light on a Dyson hand vacuum shows the level of battery charge. This light also might turn red to warn you when the hand vacuum is not operating correctly. Pay attention to this light and troubleshoot the light when it flashes red to avoid damaging the hand vacuum beyond repair. If you can't troubleshoot the vacuum, the company also might be able to assist you. Here are some troubleshooting steps to take when the red light flashes.
Is the red light flashing or is it lit constantly? If the light remains constantly lit, the battery requires charging. The red light will stay lit once the Dyson is on its charger and until it is fully charged.
Remove the filter from inside the hand vacuum and refit it into the machine. This might stop the red light from warning you that the vacuum is not assembled properly.
Allow the hand vacuum to sit at room temperature for up to an hour. Sometimes the flashing red light indicates that the machine is too hot. If hand vacuum is sitting on its charger, unplug it from the charger until the light stops flashing.
Call the Dyson Helpline if the flashing red light continues at 1-866-MY-DYSON.