Electrical (A6)Question 75 of 120
Excessive AC ripple voltage measured at the battery with the engine running usually indicates:
a.One or more failed alternator diodes
b.A weak starter
c.A blown headlight bulb
d.A stuck thermostat
Explanation
Failed rectifier diodes let AC leak through, producing measurable ripple and reduced DC output. A meter set to AC volts or an oscilloscope reveals it. This often causes charging complaints and can disturb electronic modules.
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