The regulator in every vehicle's engine is in place to regulate the amount of energy going to and coming from the vehicle's battery. The voltage regulator is a part of this system and helps keep the amount of voltage cycling through the system at a constant rate to keep the vehicle's battery charged by the generator. Sometimes, this voltage regulator will undercharge or overcharge your battery, forcing you to adjust it so that you can avoid any further problems with your car's engine. An alternator with a built-in voltage regulator cannot be adjusted.
Turn on the vehicle and open its hood. Locate the vehicle's battery terminals.
Connect the voltmeter's black connection to the battery's negative terminal and connect the voltmeter's red connection to the battery's red terminal.
Read the voltmeter reading. If the voltmeter shows that the battery is outputting below 14 volts, the regulator is not sending enough voltage to the battery. If it is outputting above 14 volts, the regulator is sending too much voltage to the battery.
Locate your vehicle's voltage regulator. See your vehicle's owner's manual for its exact location.
Remove the cover from the regulator and locate the regulator's adjustment screw or bolt. See your vehicle's owner's manual for the regulator's method of adjustment.
Tighten the adjustment screw or bolt to increase the voltage, loosen the screw or bolt to decrease the voltage. Adjust the screw or bolt until the voltmeter reads 14 volts.
Replace the regulator cover and disconnect the voltmeter from the battery terminals. Close the hood of the vehicle and turn the vehicle off.
