How to Test a Honda Alternator Without Removing It

by Lee Sallings
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The battery in your Honda is constantly supplying power to the vital systems of the car, even when the engine isn't running. When you turn the ignition key to the "Start" position, electrical power is supplied to the starter, and the engine turns over. The alternator in your Honda provides the electrical power to your vehicle after the engine starts. Testing the charging system of the Honda presents some difficulties, but this project is still within the abilities of a well-equipped weekend mechanic.

Step 1

Set the controls on your digital volt/ohm meter to the ā€œVolt D/Cā€ position. The battery in the Honda is located on the passenger's side rear of the engine compartment or on the driver's side front of the engine compartment. Locate the battery and pull back the protective rubber terminal covers. Touch the red test lead of the meter to the positive battery terminal and the black test lead of the meter to the negative battery terminal. The voltage displayed on the meter should be above 12.5 volts. If the voltage is low, charge the battery before further testing.

Step 2

Test for battery voltage at the alternator on the charging lug located on the back of the alternator. The charging lug will have a large gauge wire, covered by a rubber boot, bolted to it that supplies power to the rest of the vehicle when the engine is running. Touch the red test lead to the charging lug and the black test lead to the engine block. If no voltage is present at the charging lug, replace the charge fuse located in the under-hood fuse block. If the fuse blows immediately, check the ignition switch for melted contacts.

Step 3

Start the engine, and touch the red and black test leads to the battery. If the alternator is functioning properly, the voltage displayed on the meter will be around 13.5 volts. If the voltage displayed is the same or less than battery voltage, replace the alternator.

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