Battery Cable Alternator Test

Test the negative battery cable by using the same procedure as above for the positive cable but this time you will have the red lead of the multimeter touching the metal housing of the starter motor and the black lead of the multimeter connected to the negative battery terminal.

Battery cable alternator test.

The second you disconnect the battery the voltage regulator pegs the alternator to put out maximum power. Start vehicle and voltage on voltmeter should increase to around 13 volts and stabilize there. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. Pcm tcm electronic power steering radio etc.

But it s also possible that the alternator is actually in a bad shape but is producing enough to run the. Test alternator by connecting voltmeter on dc 20 red on positive battery terminal and black on negative battery terminal. Now about the ineffectiveness of it the vehicle will run if the alternator is producing enough juice. Testing alternator by removing battery cable can you test an alternator by removing battery cable.

Again you should see a reading of 0 3 volts or less to be. Technically yes but that test can also wind up destroying all the electronics in your car. To do a quick check on an alternator i was told that you could start the car and then remove the negative battery cable. So when you test an alternator by pulling battery cable you increase the probability of killing that regulator.

With no battery in the circuit to act as a buffer the alternator can put out up to 150 volts depending on engine rpm. Dear tom and ray.