Orbital sander battery not charging - any ideas?

Hey all, my Ryobi 18V orbital sander stopped taking a charge. I've got two batteries both won't charge on the charger. The batteries work fine in my drill though. What gives? Checked for debris, nothing obvious. Any thoughts?

Odd that both batteries work in the drill but not on the sander. Could be a loose connection in the sander's battery terminal. Check the pins on the sander itself. Sometimes they get bent or gunked up. Try a little contact cleaner on a q-tip.

Also make sure the battery is sliding in all the way. I had a sander where a piece of dust got behind the battery and prevented full contact. Use compressed air to blow out the battery slot.

+1 on checking contacts. If that doesn't work, might be a charger issue. Even if charger light comes on, it might not be outputting correct voltage. Test with a multimeter if you have one.