To change a voltage regulator in a car, detach the cables from the battery. Remove the positive cable first before removing the negative one. Remove the rear cover of the alternator, and locate the voltage regulator, which is either between the alternator and the battery or on the back of the alternator. Unplug the four cables on the old regulator, and plug in the new regulator.
Disconnect the regulator from the alternator by removing adhering bolts using a screwdriver or a wrench. Identify two carbon brushes at the bottom of the regulator. Remove them, and use sandpaper to clean their contact ends. Insert the carbon brushes into the new regulator, and ensure the wear patterns on the new regulator match the patterns on the brushes.
Insert the new regulator by aligning it with the holes on the alternator or car frame. Use an adjustable wrench or a screwdriver to secure the voltage regulator with bolts, and then attach wires. Reattach the battery cables, and ensure that each is connected to the contact it was removed from. Using a wrench, tighten all the wires appropriately.
Start the car, and run it at about 1,000 rpm. Check the voltmeter on the car’s dashboard to determine the battery voltage. Adjust the voltage regulator if the voltage is not within the range of 13.5 to 14.5. Recheck it after making the adjustments.