Harley Voltage Regulator Symptoms

Voltage regulators are common parts to fail on a motorcycle, especially when exposed to high heat and vibration. A Harley voltage regulator senses when the battery’s charge has dropped below 13.5 volts then sends electric current to the coil. A bad voltage regulator will cause many problems, which are identified in this article.

The following are Harley voltage regulator symptoms;

#01. Battery light illumination in the engine compartment

This is caused by the voltage regulator overheating causing the internal diodes in the regulator to fail. This causes the light to come on when a load is applied to the charging system. This is caused by a failing regulator.

#02. No power at all

A regulator failure can result in no power supply to any device that uses electricity from your bike’s charging system. If you find yourself out in inclement weather with no way to operate some of these devices, it may be time for a regulator check.

#03. Hard starting

This is due to the higher current draw that occurs when cranking an engine. If your bike struggles to turn over frequently, you may need to replace the voltage regulator and rectifier.

#04. Engine misfiring under load

As the voltage regulator gets older, its ability to regulate charging voltage decreases. This causes the engine to run too hot and can result in a lower rpm under load. If your bike misfires under load or notices an rpm drop, you should check the charging system.

#05. No Power to high beam or low beam lamps when headlights are turned on

The charging system energizes the high and low beam lamps when the headlights are turned on, but it’s not happening in this case. This is another symptom of a failing voltage regulator.


Voltage regulators do have a finite life span and will eventually fail. The good news is that it’s easy to change, and in almost all cases, it is not expensive either. Keeping up with regular maintenance can save you money in the long run.

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Writer @ Motorcycleall.

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