Welcome to JUST ANSWER small engines, let me try to help you !! Did you try your charger on your friends cart? If it doesn't work on either, what usually goes out on theses auto chargers is the circuit board with the lights. It requires dismantling the charger and replacing the timer circuit board. There is a way to bypass the card and be sure the charger transformer and diodes are good, but I hesitate to try and explain how it is done. My thought is , you need to have the charger checked by someone who knows chargers. Sorry.