Q: My car will not start. I am getting a clicking sound when I turn the key. But when I try to jump-start the car it starts right up. After I jump-started it, I let it run for 20 minutes and then shut it off. When I went to try to start again, it just clicked. I jump-started it yet again, but this time I let the cables stay attached for 10 minutes. Now the car starts several times with no problem. What is happening here?
A: Sounds like an alternator. When you left the cables on for 10 minutes the other car’s charging system may have recharged your battery. The best way to tell is to use a multimeter set to DC Volts to measure the voltage at the battery while your car is running. With the car running you should get a reading between 13.5 to 14.5 DC volts at the battery. If you are only receiving a reading of 12.0 to 12.6 DC volts while the car is running, then the alternator is probably bad.