Output Voltage Check

The purpose of this test is to check that the electronic voltage regulator maintains the output voltage at the required level.

Preparation for Check

PROCEDURE

1. Before testing, check the following items:
– the battery installed in the vehicle must be fully charged;
– check the alternator drive belt tension.
2. Turn the ignition key to the "OFF" position.
3. Disconnect the wire from the negative battery terminal.
4. Connect a digital voltmeter between the alternator "S (L)" terminal and ground. Connect the positive voltmeter lead to the alternator "S (L)" terminal.
5. Disconnect the wire from the alternator "B" terminal.
6. Connect a DC ammeter with a 0–100 A measuring range in series between the "B" terminal and the wire disconnected from the alternator. Make sure the negative ammeter lead is connected to the wire disconnected from the alternator.

7. Connect the tachometer, and connect the wire to the negative battery terminal.

Inspection

PROCEDURE

1. Make sure the voltmeter scale is clearly visible for reading the voltage.
The voltmeter should show the battery voltage.
If the voltmeter shows 0 V, the electrical circuit connecting the alternator "S (L)" terminal and the positive battery terminal is open, or the fusible link is blown.
2. Start the engine and turn off all electrical loads.
3. Increase the engine speed to 2,500 rpm and when the current drops below 10 A, read the voltage on the voltmeter.

Check Result

PROCEDURE

1. If the voltage is within the specified value, the voltage regulator is serviceable and operating normally. If the voltage differs from the specified value, the voltage regulator or the alternator is faulty.

2. After completing the alternator limit current test, return the engine to idle and turn the ignition off.
3. Disconnect the wire from the negative battery terminal.
4. Remove the tachometer, voltmeter and ammeter.
5. Connect the wire to the alternator "B" terminal.
6. Connect the wire to the negative battery terminal.