Diagnosis

A charging circuit wiring diagram for generator connection is shown in "Charging System/ Alternator/ Description and Operation". To avoid damage, always follow these precautions:

CAUTION:
- Do not mistake polarities of IG terminal and L terminal.
- Do not create short circuit between IG and L terminals. Always connect these terminals through lamp.
- Do not connect any load between L and E.
- When connecting charger or booster battery to vehicle battery, see Battery System

Trouble in charging system will show up as one or more of the following conditions:
- Faulty charge indicator light operation.
- Undercharged battery as evidenced by slow cranking or indicator clear with red dot.
- Overcharged battery as evidenced by excessive spewing of electrolyte from vents.

NOISY GENERATOR INSPECTION
Noise from a generator may be caused by a loose drive pulley, loose mounting bolts, worn or dirty bearings, defective diode, or defective stator.

GENERATOR TEST (WHEN BATTERY IS UNDERCHARGED)
This condition, as evidenced by slow cranking or indicator clear with red dot can be caused by one or more of the following conditions even though indicator lamp may be operating normal. Following procedure also applies to vehicle 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. Refer to "GENERATOR BELT".
3. If battery defect is suspected, refer to "BATTERY DIAGNOSIS".
4. Inspect wiring for defects. Check all connections for tightness and cleanliness, battery cable connections at battery, starting motor and ignition ground cable.




5. Connect voltmeter and ammeter as shown in the figure.

NOTE: Use fully charged battery.

No-load Check




1. Run engine from idling up to 2,000 rpm with all accessories turned off and read meters.

Specification for undercharged battery inspection:
Current:10 A maximum Voltage:
14.4 - 15.0 V (at 20 °C (68 °F)) for 60 A and 70 A types
14.2 - 14.8 V (at 20 °C (68 °F)) for 80 A type

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

2. If voltage is higher than standard value, check ground of brush. If brush ground is correct, replace IC regulator.
3. If voltage is below or in standard value, perform the following procedure.
a. For 60 A and 70 A types
i. Run engine at 2,000 rpm and turn on head light and heater motor.
ii. Measure current and if less than 20 A, repair generator.

b. For 80 A type




i. Ground "F" terminal and start engine, then measure voltage at "B" terminal as shown in the figure.
- Voltage is higher than standard value
It is considered that generator itself is good but IC regulator has been damaged, replace IC regulator.
- Voltage is lower than standard value:
Generator itself has problem, check the generator.

Load Check (For 80 A Type)
1. Run engine at 2,000 rpm and turn on head light and heater motor.
2. Measure current and if it is less than 30 A repair or replace generator.




GENERATOR TEST (WHEN BATTERY IS OVERCHARGED)
1. To determine battery condition, refer to "BATTERY DIAGNOSIS".
2. If obvious overcharge condition exists as evidenced by excessive spewing of electrolyte, measure generator "B" terminal voltage at engine 2000 rpm.
3. If measured voltage is higher than upper limit value, proceed to disassembly section of generator service.
4. Check ground of brushes. If brushes are not grounded, replace IC regulator. Then check field coil for grounds and shorts, referring to "INSPECTION" of "GENERATOR ASSEMBLY" under "UNIT REPAIR OVERHAUL".