How to Diagnose a Bad Starter Motor

Video Transcript

"There it happens, you come out to your car in the morning and turn the key in and nothing happens. You're all set to go to work and it doesn't crank over and nothing happens at all. We've got several possibilities that can cause a problem like that, but one of the things that might be suspected, is a bad starter motor. So we're going to take a look at some of the procedures that would take place in order to determine, if the starter motor itself is bad. The first thing we're going to start by doing is making sure that the battery is good. So we're going to perform a load test on this battery by hooking up this volt amp tester to the battery. The hook up is very much like hooking up a set of jumper cables. And we can see that the battery is 12.5 volts which is a good thing to start with. And then based on this battery's 300 cold cranking amp rating, we're going to adjust the load knob, which applies a load much like a starter would, up to 300 amps. And we're going to see if they can keep the voltage up. And so we do this for 15 seconds, at the end of the fifteen seconds, it is still over 9.6 volts. So this battery should have a sufficient capacity in order to start this vehicle, so the battery is not the problem."