I discovered a Fix for cartos that do not work at all. No vapor...no nothing...just not working. I have several new cool carts that I had to fix. Take a needle nosed pliers or something else that would work, and turn the round connector in the screw-in part of the carto. Turn it counter-clockwise about a quarter turn. It lifts that contact, and then it makes connection to the contact on the battery better. That has fixed my problems. GOOD LUCK!!