Indicator light going on: This also includes the battery light. Weak or dimming lights, especially noticeable at night: An alternator problem is especially likely if the lights brighten with an increase in RPM. Other electrical malfunctions: The alternator generates power for a vehicle's electrical systems. Strange noises: A problem with an alternator's belt or pulley may cause a squealing sound, while a problem with an alternator's internal bearings may cause a grinding or growling noise. A burning smell: This may indicate a problem with the alternator's belt or pulley. A healthy battery that cannot accept or hold a charge: Always have your “dead” battery tested before replacing it. A faulty alternator could be failing to recharge the battery during operation. Related: Learn more about battery testing