How To Test A Laptop Charger Without Multimeter. If the LED does not work do not come to any conclusions yes. Take the following general steps obviously the process will vary slightly depending on your operating system.
Without a multimeter you can use your tongue to test voltages lower than 9V or so. Cut an old USB-C cable in half and strip the ends of the wires. If you just got a brand new battery and your car is not starting then you definitely have a faulty alternator on your hands.
Turn off the laptop.
More info about amperage reading here. This example uses a Toshiba Satellite Laptop that will not power on. Next please realize that you will only be able to measure the DC voltages. The car dies after a jump start.
