BELT TENSION
Note. Drive belt tension is regulated by automatic tensioner. For proper belt routing, see DRIVE BELT ROUTING in SPECIFICATIONS & DRIVE BELT ROUTING article under COOLING SYSTEM (MECHANICAL) in ENGINES.
ON-VEHICLE TESTS
| CAUTION | To avoid damage to the internal parts (power transistor) of the generator, do NOT apply direct battery positive voltage to the generator terminal "D". (Scheme 10) |
Note. Prior to performing generator testing, turn OFF all electrical components. Place transmission in NEUTRAL, apply parking brake.
GENERATOR CURRENT
Note. Since the charging current decreases rapidly after starting the engine, carry out the following procedure quickly, and read the maximum current value.
- Verify that the battery is fully charged.
- Verify that the drive belt deflection/tension is correct.
- Disconnect the negative battery cable.
- Connect a tester capable of reading 120 amps or above, between generator terminal "B" and the wiring harness connector.
- Connect the negative battery cable.
- Turn off all electrical loads. Start the engine. Increase engine speed to 2500 RPM.
- Turn headlights (high-beam), blower motor (high), rear window defroster and brake lights on and verify that the current reading increases more than minimum current value - 70 percent of the nominal output current (nominal output current: 90 amps, ambient temperature - 68°F (20°C), voltage 13.0-15.0 volts, while both engine and generator are cold. If it is not as specified, go to «PCM AND GENERATOR SHEARING INSPECTION»(ref-166663-S27814539832004092400000) under SYSTEM TESTS.
GENERATOR VOLTAGE
- Verify that the battery is fully charged.
- Verify that the drive belt deflection/tension is correct.
- Turn off all electrical loads.
- Start the engine and verify that the generator rotates smoothly without any noise while the engine is running.
- Using DVOM, measure the battery voltage at the battery and by backprobing at generator harness connector terminals "D" and "P". See «GENERATOR OUTPUT»(ref-166663-S25065634022004092700000) table. (Scheme 10)
| Generator Terminal | Ignition ON - Volts | Idle - Voltage At 68°F (20°C) |
|---|---|---|
| B | Battery Voltage | 13-15 |
| P | About 1.0 Or Less | About 3.0-8.0 |
| D | About Zero | (1) |
| (1) Turn on the following electrical loads, headlights, blower motor and rear defroster and verify voltage increases. | ||
| (1) | Turn on the following electrical loads, headlights, blower motor and rear defroster and verify voltage increases. |
GENERATOR OUTPUT
Scheme 10
BEARING
Check bearing for abnormal noise, looseness and sticking. Replace bearing as necessary.
BRUSHES
Note. If any brush is worn almost to or beyond the limit, replace all of the brushes.
Inspect brushes for wear. Measure brush length. (Scheme 11) Replace as necessary. See GENERATOR SPECIFICATIONS.
Scheme 11
BRUSH SPRING
Measure the force of the brush spring using a spring pressure gauge. Read the spring pressure gauge at the brush tip projection of 0.079" (2 mm). (Scheme 12) Replace as necessary. See GENERATOR SPECIFICATIONS.
Scheme 12
RECTIFIER
Using DVOM, check diodes for continuity. See RECTIFIER DIODE CONTINUITY table. (Scheme 13) Replace rectifier if not as specified.
| Tester Negative Probe | Tester Positve Probe | Continuity |
|---|---|---|
| E | P1, P2, P3 & P4 | Yes |
| B | P1, P2, P3 & P4 | No |
| P1, P2, P3 & P4 | E | No |
| P1, P2, P3 & P4 | B | Yes |
RECTIFIER DIODE CONTINUITY
Scheme 13
ROTOR
- Using DVOM, measure the resistance between the slip rings. (Scheme 14) If resistance is 1.7-2.1 ohms, go to next step. If resistance is not 1.7-2.1 ohms, replace rotor.
- Using DVOM, verify there is no continuity between the slip ring and core. (Scheme 15) If continuity does not exist, go to next step. If continuity exists, replace the rotor.
- Inspect the slip ring surface condition. If slip ring surface is rough, use a lathe or fine sandpaper to repair.
Scheme 14
Scheme 15
STATOR COIL
- Using DVOM, check for continuity between the stator coil leads. (Scheme 16) If continuity exists, go to next step. If continuity does not exist, replace stator.
- Verify that there is no continuity between the stator coil leads and the core. If continuity exists, replace the stator coil. (Scheme 17)
