Onan Voltage Regulator Troubleshooting

Onan Voltage Regulator Troubleshooting

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Recreational vehicles (RVs) use auxiliary generators to power appliances, such as air-conditioning units. Onan produces RV generators that have a voltage regulator assembly for power control. Voltage regulators may require troubleshooting steps if they malfunction.


The RV generator's voltage regulator component receives voltage from the machine's control board. That voltage passes through the voltage regulator, where it stabilizes at a constant value, depending on the generator's specifications. The voltage powers the generator motor's brushes for generator ignition and use.


Locate the voltage regulator inside the generator's control box. Test the voltage regulator's pin 7 with a voltmeter. The instrument should display 12 volts on pin 7. Attach the voltmeter to the motor's brushes. The voltmeter should reflect 10 to 11 volts across the brushes. The voltage regulator has failed if the voltmeter displays no voltage across the brushes.


During voltage regulator testing, verify that the voltmeter's leads are properly secured. When the positive lead is attached to pin 7, the negative lead must be attached to ground. The displayed voltage value is incorrect if the negative lead is not grounded.

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