My charger displayed cold/hot pack delay during charging

This is indicating the battery is too hot to charge, usually after coming off the tool right after some hard work. During the charging process the battey heats up so if you charge a hot battery, thereby making it hotter, you shorten the lifespan of the battery considerably. If you are getting a hot/cold pack delay indication on the charger, it should automatically start charging once the battery has cooled down sufficently.

Unplug at wall then plug back in a few times.. worked for me. Also if wont charge then get a 12v batter charger and excite it a few times or charge it for a few minutes to put some life back into it.. if that dont work open the battery and find the dead cell and try shock it back to life if that dont work swap that cell with a better one from any old battery.. better yet if it's the old NiCd battery then rip out all the old cells and insert lithium cell pack just solder the terminals and your away laughing