What Are Signs of a Bad Voltage Regulator?

Warning lights, unpredictable engine performance and dimming or pulsating lights are all signs of a faulty voltage regulator. A number of symptoms can develop if the voltage regulator fails to deliver sufficient voltage. Warning lights may not inform the operator of such a failure until it is too late, so it is important to be aware of the associated issues.

Ignition systems, fuel pumps and computer controls all rely on sufficient power to function properly. Engine performance wanes or sputters if voltage drops. The engine also sputters if headlights or other components are activated when the power supply is too low.

Voltage regulators also fail by generating too much power. In these instances, the tail lamps and headlight bulbs abruptly die. The owner can check the charging systems if lamps or bulbs are frequently blowing out. Heavy venting occurs when the battery receives too much power. This releases substantial acidic vapors, which corrode nearby surfaces. Look for signs of corrosion near the battery, but do not touch the battery if it emits a vapor or makes strange noises.

Charging systems that fail to illuminate can also indicate a problem with the regulator. Owners should check the operation of the lights and warning indicators by turning on the ignition switch without starting the engine. The lights should come on and stay lit until the engine starts.