Alternator: Testing and Inspection
Generator Warning Light1. Verity that the battery is fully charged.
2. Verify that the drive belt deflection/tension is correct.
3. Turn the ignition switch to ON and verify that the generator warning light comes on.
4. If not, inspect the generator warning light and wiring harnesses between the battery, and generator warning light and between the battery and generator terminal L.
5. Turn the ignition switch to START and verify that the generator warning light goes out after engine starts.
6. If not, inspect the generator.
Generator Voltage
1. Verify that the battery is fully charged.
2. Verify that the drive belt deflection/tension is within the specification.
3. Turn off all electrical loads.
4. Turn the ignition switch to START and verify that the generator turns smoothly without any noise while the engine is running.
5. Measure the voltage at the terminals shown in the table.
Standard Voltage
6. If not, disassembly and inspect the generator.
Current
1. Verify that the battery is fully charged.
2. Verify that the drive belt deflection/tension is correct.
3. Disconnect the negative battery cable.
4. Connect a circuit tester, capable of reading 120 A or over, between generator terminal B and the wiring harness.
5. Connect the negative battery cable.
6. Turn all electrical loads off.
7. Start the engine and increase the engine speed to 2,000-2,500 rpm.
8. Turn the following electrical loads on and verify that the current reading increases.
^ Headlights
^ Blower motor
^ Rear window defroster
NOTE:
^ Current required for generating power varies with electrical loads applied.
Standard current (Reference)
Measuring conditions
Room temperature: 20 °C (68 °F)
Voltage: 13.5 V
Engine hot
9. If generator terminal B current will not increase, disassemble and inspect the generator.
Generator Inner Parts
Rotor
1. Wiring damage
1. Measure the resistance between the slip rings by using an ohmmeter.
Specification
2.4 - 2.9 Ohms [20 °C (68 °F)]
2. If it is not within the specification, replace the rotor.
2. Ground of field coil
1. Check for no continuity between the slip ring and the core by using an ohmmeter.
2. Replace the rotor if there is continuity.
3. Slip ring surface
If the slip ring surface is rough, use a lathe or fine sandpaper to repair it.
Stator
1. Wiring damage
1. Check for continuity between the stator coil leads by using an ohmmeter.
2. Replace the stator if there is no continuity.
2. Ground of stator coil
1. Check for no continuity between the stator coil leads and the core by using a circuit tester.
2. Replace the stator if there is continuity.
Brush
If any brush is worn almost to or beyond the limit, replace all of the brushes.
Standard
21.5 mm (0.846 in)
Minimum
8.0 mm (0.315 in)
Brush spring
1. Measure the force of the brush spring by using a spring pressure gauge. Read the spring pressure gauge at the brush tip projection of 2 mm (0.079 in).
2. Replace the spring if necessary.
Standard force
3.2-4.3 N (0.32-0.44 kgf, 0.71-0.96 lbf)
Minimum
1.8 N (0.18 kgf, 0.4 lbf)
Rectifier
1. Check for continuity of the diodes by using an ohmmeter.
2. Replace the rectifier if not as specified.
Bearing
1. Check for abnormal noise, looseness, and sticking.
2. Replace if necessary.