My Milwaukee impact driver won't charge - any ideas?

Hey guys, so my Milwaukee M18 impact driver just stopped charging. I plugged it in, the light on the charger blinks red and green, and the battery won't charge. It's about 2 years old, used lightly. Any ideas what's wrong? I'm about to tear my hair out.

Have you tried a different outlet? Sometimes those chargers are picky. Also, check the contacts on the battery and charger for dirt or corrosion. A little rubbing alcohol on a q-tip can work wonders. If that doesn't do it, might be a dead cell in the battery pack. I had a similar issue with a Ryobi and ended up just buying a new battery.

Don't buy a new battery yet! Blinking red and green usually means the battery is too hot or too cold. Let it sit for an hour and try again. If that doesn't work, try the 'reset' trick: stick a flathead screwdriver in the slot between the battery and the charger (carefully!) to disconnect the internal BMS, then reconnect. That sometimes resets it. But if you do that, you void the warranty, so beware.

Yeah, I second the temp thing. I once left a battery in my truck on a hot day and it did exactly that. Let it cool down and it charged fine. If you've tried that and it's still blinking, check the charger itself. Do you have another M18 battery to test? That'll tell you if it's the battery or the charger. I've seen those chargers go bad more often than the batteries tbh.

Hey thanks for the tips! I let it cool down for a couple hours and tried again, but still the same. I'll try the reset trick, and if that doesn't work, I'll borrow a buddy's battery to test the charger. Appreciate the help guys, I'll update if I figure it out.