Craftsman power drill - batteries wont recharge. When I insert dead batteries into the charger The green light ''Fully charged'' comes on and stays on. The batteries do not charge as when they are inserted into the drill there is no power.

Check charger connecting cables and measure its output volt if its OK then problem can possible in the battery if not OK then you have to check charger fuse which fix in front panel .need to replace it .
Hope after that it will work .

run all 3 batteries down to full dead then fully recharge. some times this can help

It depends on the charger taht comes with this drill, the dumb charger will just keep on charging the batteries even when it if fully charge and does not sop, which will be bad for the batteries, the smart charger (more expensive and has electronics inside the charger) will go into floating charge when the batteries are fully charge which will prevent the batteries from being overcharged. If in doubt, remove it from the charger after overnight charging.

It sounds like your charger is faulty. Try to measure the voltage of the batteries. If the nominal (workingh voltage of the batteries are 19,2 volt, then they should invrease to about 22 volt while in the charger. If the voltage does shoot up when the charger is on, maybe even to 25 volts, (which should turn the green light on) the new battries are dead!
It happens!
The other possibility is that the batteries are OK & fully charged!
But!
Your sander is damaged. Again, try & measure the voltage in the sander, before & after you switch it on. A large drpop in voltasge can indicate the sander drawing too much current. Also try them in another machine if you can.
Andy

This is not right. They should last much longer then that. I have one of the more expensive 18V lithium batteries (the one with the button on it that tells you if it needs charging or not) and I can use mine almost all day before it needs to be recharged. I do construction work and I use my Ryobi products almost all day. Either both batteries are bad (I don't believe that is the case) or the charger is not charging them all the way to a full charge. With this charger, you do need to make sure that you remove the batteries as soon as the green light comes on. It is not good on these batteries to stay charging after they are fully charged. You also should not leave the charger plugged in without any batteries charging.Please tell me more about the charger. When you plug in the charger, does the red light come on? When you plug in a battery, does the red light stay bright and the green light blink? Does the red light go off and the green light stay on bright when you remove it from the charger?
If the charger is not working correctly, then return it for a new one.

If both yellow and green LEDs come on, this indicates
a deeply discharged or defective battery pack.
Allow the battery pack to remain in the charger for 15
to 30 minutes. When the battery pack reaches normal
voltage range, the red LED should come on. If the
red LED does not come on after 30 minutes, this may
indicate a defective battery pack and should be
replaced.
n After normal usage, a minimum of 1 hour of charging time
is required to fully recharge battery pack.

check the connections on the unit. some times thy don't make contact. and check the battery to.

If both yellow and green LEDs come on, this indicates
a deeply discharged or defective battery pack.
Allow the battery pack to remain in the charger for 15
to 30 minutes. When the battery pack reaches normal
voltage range, the red LED should come on. If the
red LED does not come on after 30 minutes, this may
indicate a defective battery pack and should be
replaced.
After normal usage, a minimum of 1 hour of charging time
is required to fully recharge battery pack.

Is this an old battery? Batteries can fail and not charge after a lot of use. If it's new, run it all the way dead, then try to recharge .

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

Either the battery is hot from use or has been in the sun, let it cool down, then try again.