The blinking red light indicates a problem with the battery pack or the charger itself. The specific fault is either a 'PROBLEM PACK OR CHARGER' or a 'HOT/COLD DELAY' condition.
- First, disconnect the battery pack from the charger and unplug the charger from the outlet.
- Check the battery terminals and the charger cavities for any conductive foreign material like metal dust, chips, or grinding debris. Clean them out if present.
- Let the battery pack and charger cool down or warm up to room temperature if they were in an extreme environment.
- Reconnect everything. If the light is solid red, it's charging. If it's solid green, the pack is charged.
If that didn't work, the issue is likely a faulty battery pack or a damaged charger. Do not attempt to disassemble the charger. If the charger has received a sharp blow, been dropped, or has a damaged cord or plug, take it to an authorized service center. Never try to charge the battery pack with any charger other than the specified DeWalt one.
Heads up: Always unplug the charger from the power supply when there is no battery pack in the cavity to prevent a potential short.