Generator Test (Undercharged Battery Check)

Generator Test (Undercharged Battery Check)

This condition, as evidenced by slow cranking or indicator clear with dark or light yellow dot can be caused by one or more of the following conditions even though indicator light may be operating normal.

The following procedure also applies to cars with voltmeter and ammeter.
1. Make sure that undercharged condition has not been caused by accessories left on for extended period of time.
2. Check drive belt for proper tension.
3. If battery defect is suspected, refer to Battery Description.
4. Inspect wiring for defects. Check all connections for tightness and cleanliness, battery cable connections at battery, starting motor, ignition ground cable and no "C" terminal circuit at ground.
5. Connect switch (6), load (5), battery (4), voltmeter (3) and ammeter (2) to generator (1) as shown in figure.
Voltmeter:Set between generator "B" terminal and ground.
Ammeter:Set between generator "B" terminal and battery (+) terminal.





NOTE: Use fully charged battery.

6. Measure current and voltage.

No-Load Check
1. Run engine from idling up to 5000 rpm and read meters.

NOTE: Turn off switches of all accessories (wiper, heater etc.).

Specification for undercharged battery (No-load check)
Current: 10 A
Voltage: 14.2 - 14.8 V (at 20 °C, 68 °F)





NOTE: Consideration should be taken that voltage will differ somewhat with regulator case temperature as shown in figure.




2. Using service wire, ground "C" terminal (1) of generator.
3. Measure voltage between "B" terminal of generator and body ground.

Voltage: 12.5 - 13.1 V (at 20 °C, 68 °F)

^ If voltage is higher than standard value
If voltage is higher than standard value, check ground of brushes.
If brushes are not grounded, replace IC regulator.
If voltage is lower than standard value, proceed to the following check.

Load Check
1. Run engine at 5000 rpm and turn on head light and heater motor.
2. Measure current and if it is less than 30 A repair or replace generator.