How to Change a Voltage Regulator

by Mark Morris
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The voltage regulator in your automobile controls the voltage in your electrical system, maintaining a constant current to run the electrical and electronic accessories in your car. It maintains a constant voltage of between 13 to 15 volts, depending on your automobile. The extra voltage above your battery's voltage, which is 12 volts, allows the battery to be recharged. There are two types of regulators, contained electronic regulators and contact point regulators. Unless you have a classic car, more than 25 years old, your regulator will be of the electronic variety and is either attached to your alternator or located remotely.

Step 1

Use a wrench to detach the cables from the battery. The battery is typically located under the hood, directly behind the grill of the automobile, on either the right or left side. It has two cables attached. Detach the positive cable first, it will be labeled with a "+" sign. Loosen the nut holding the cable by turning it counterclockwise. Remove the negative cable in the same way.

Step 2

Locate the voltage regulator. It is either in a black plastic box on the back of your alternator, which will be labeled on the belt diagram under the hood of your car or in line in the battery cable between the alternator and the battery. Consult a repair manual for your make and model for more specifics.

Step 3

Position the new regulator over the old for remote regulators, inline with the battery cable and not attached to the alternator and unplug each cable from the old regulator and plug it into the new regulator. There may be up to four cables, depending on the make and model. For cables attached with screws, loosen the screws by turning them counterclockwise with a screwdriver. Attach the cables by fitting them onto the corresponding screws on the new regulator. Tighten the screws with the screwdriver. For integrated regulators, those attached to the alternators, move directly to the next step.

Step 4

Remove the screws or bolts holding the regulator to the car frame, or alternator, using a wrench or screwdriver. The type of mounting hardware depends on the car model. Position the new regulator, aligning it with the holes on the alternator or car frame. Install the mounting screws through the holes in the new regulator and tighten them, by turning them clockwise.

Step 5

Replace the battery cables and tighten the cables with the wrench, making sure to attach each cable to the contact you removed it from, positive to positive and negative to negative.

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