Up next in How to Take Care of Your Car (29 videos)
Take care of your automobile and it won't strand you. Howcast helps you keep your ride running smoothly with this video series on car maintenance.
You Will Need
- Car battery
- Owner's manual (optional)
Find the battery
Locate your car's battery, usually located on the left side of the engine if you're facing the front of the car. If it's not there, check the right side. Some cars even have their batteries under a seat in the middle of the car.
Connect at the voltmeter
Connect the voltmeter to the battery while the car is off. Connect the red positive wire on the meter to the positive battery terminal, and connect the black wire on the meter to a bare metal grounding source, such as a nut or bolt on your car's frame.
Read the battery's voltage
Read the voltage on the meter to determine how many volts your battery is producing. Twelve is average, and if goes much lower than 11, you need a replacement.
Turn the engine on
Disconnect all wires and turn the engine on and reconnect the meter to the battery.
Read the voltage
Read the voltage on the meter as the car is running. If the voltage with the car running is higher than the voltage when the engine is off, then the alternator is fine. If it's lower, your alternator needs to be repaired or replaced.