Professional diagnositic tools 2Turn your volt meter on. Switch it to the DC setting.

Tips on how to Verify the Alternator Output on a GM

1Start your GM automobile.

2Turn your volt meter on. Switch it to the DC setting.

3Place the red lead from the volt meter towards the positive red terminal of the GM battery.

4Place the black lead from the volt meter for the negative black terminal from the GM battery.5Read the volt meter screen. It must be in between 13.

5 and 14.4 volts. A battery only has 12 volts Professional diagnositic tools, but when the vehicle is running Auto diagnostic tools, the alternator spikes the volts to 14 to overcome resistance.

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