DESCRIPTION
Nippondenso alternators are conventional 3-phase alternators utilizing 3 positive and 3 negative diodes to rectify current. Charging system voltage is controlled by an internal Integrated Circuit (IC) voltage regulator, or external voltage regulators. Some Toyota models use engine, ignition, and charging light relays.
| Model | Amps | (1) Part No. | |
|---|---|---|---|
| Impulse (2) | 75 | 8-94408-674-0 | |
| I-Mark | |||
| With A/C | 60 | 8-94137-345-2 | |
| Without A/C | 50 | 8-94101-255-1 | |
| (1) Vehicle manufacturer's part number. (2) With 4ZC1-T engine. Impulse with G200Z engine uses Hitachi alternator. | |||
| (1) | Vehicle manufacturer's part number. |
| (2) | With 4ZC1-T engine. Impulse with G200Z engine uses Hitachi alternator. |
NIPPONDENSO ALTERNATOR APPLICATION
Alternator Tester Hook-Up. Scheme 1
Alternator Tester Diagnostic Charts. Scheme 2
PRELIMINARY INSPECTION
Check alternator wire harness connections and drive belt tension. Battery must be fully charged.
ALTERNATOR OUTPUT TEST
- Set Alternator Tester (J-35311 ) switch to 12-volt position. Connect alternator harness to tester. (Scheme 3) Connect White/Red wire to alternator harness.
- Connect harness to alternator "L" wire (White/Red). Connect Black alligator clip to negative battery terminal. Connect Red alligator clip to positive battery terminal.
- Turn ignition switch to "ON" position. Check instrument panel charge indicator light. Start and run engine at 1500 RPM. Turn on low beam headlights. After 10 seconds, check lights on alternator tester. Tester will indicate alternator condition. (Scheme 4)
Note. After starting or stopping engine, Yellow light on tester may come on for about 5 seconds. This is normal.
Rotor
- Check rotor for open field windings by using an ohmmeter across slip rings. Rotor resistance should be 2.8-3.0 ohms for all models.
- Check rotor for shorts to ground by connecting ohmmeter between slip ring and rotor shaft. Ohmmeter should show no continuity. Check slip rings for wear or pitting. Turn rotor on lathe if necessary. Check bearing and replace if necessary.
Stator
Connect ohmmeter between 2 stator leads. Ensure there is continuity between all stator leads. Connect ohmmeter between each stator lead and metal core. Ohmmeter should show no continuity. If continuity is indicated, stator must be replaced.
Scheme 3
- With rectifier assembly on bench, contact diode plate with one probe and each of the 3 diode leads with other probe. Note ohmmeter reading. Reverse probes and repeat test. Check all diodes in this manner.
- All diodes should show a low reading in one direction and NO reading in opposite direction. If any rectifier diode is defective, replace rectifier assembly. (Scheme 3): Testing IC Voltage Regulator
- On all models, set ohmmeter to x100 ohm scale. Check for continuity between terminals "B" and "F". There should be continuity in one direction only.
Exploded Alternators. Scheme 4
Brushes
- Check for cracks and minimum length of .18-.22" (4.5-5.5 mm). If damaged or worn, replace brushes. Brushes should slide smoothly in holders. Install new springs when replacing brushes. Solder brush wire.
- New brush protrusion should be .79" (20. mm) for diesel engine equipped models, and .41" (10.5 mm) for all other models.
REASSEMBLY
- To assemble, reverse disassembly procedure. Press brushes into holder against spring tension. To prevent brushes from falling, insert a wire through hole in rectifier, end housing and brush holder.
- Press rear bearing onto rotor shaft. Pack drive end bearing with grease, and install. Install felt ring, cover, and bearing retainer (if equipped). Tighten body screws and remove brush retaining wire. Ensure stator terminal insulators are in place, otherwise alternator may short to ground.