Alternator & Regulator Toyota 4Runner II

DESCRIPTION

Nippondenso 3-phase alternators utilize 3 positive and 3 negative diodes to rectify current. Charging system voltage is controlled by an internal Integrated Circuit (IC) voltage regulator. Some models use engine, ignition, and charging light relays.

ADJUSTMENTS

4-CYLINDER BELT ADJUSTMENT (1)

6-CYLINDER BELT ADJUSTMENT (1)

V6 BELT ADJUSTMENT (1)

Scheme 1

1. Disconnect alternator terminal "B" wire. Using an ammeter and voltmeter, connect negative ammeter lead to disconnected alternator terminal "B" wire and positive lead to alternator terminal "B". Connect voltmeter positive lead to alternator terminal "B" and negative lead to ground. (Scheme 1)
2. Start engine and increase engine speed to 2000 RPM. Voltmeter and ammeter should read according to specification. See «ALTERNATOR OUTPUT SPECIFICATIONS»(/toyota/4runner/ii-1987-1995/remont/charging-system/#alternator-regulator) table.
3. If voltage is more than specified, replace IC regulator. If voltage is less than specified, ground "F" (full field) terminal. (Scheme 2)
4. If voltage now climbs above specified range, replace IC regulator. If voltage remains below specified range, repair or replace alternator.

ALTERNATOR OUTPUT SPECIFICATIONS @ 2000 RPM

Scheme 2

LOAD TEST

Note. During load test procedure, if voltage reading is low due to a fully charged battery, disable ignition system and crank engine for about 15 seconds to partially discharge battery (if necessary).

1. Connect an ammeter as described in «NO-LOAD TEST»(/toyota/4runner/ii-1987-1995/remont/charging-system/#alternator-regulator) step 1). Start engine. Turn on high beam headlights and place heater control on HI.
2. Increase engine speed to 2000 RPM and check ammeter reading. Ammeter should read more than 30 amps. If amperage is less than specified, repair or replace alternator.

Scheme 3

1. Charge light relay is located above right kick panel. Using an ohmmeter, connect ohmmeter positive lead to charge light relay terminal No. 4 and negative lead to terminal No. 3. See STEP 1 in (Scheme 3).
2. Ohmmeter should indicate continuity. Reverse ohmmeter leads. Ohmmeter should now indicate no continuity.
3. Connect ohmmeter between terminals No. 1 and 2. Ohmmeter should indicate no continuity. If charge light relay does not test as indicated, replace relay.
4. Check charge light relay operation. Connect positive side of battery to terminal No. 3. Connect negative side of battery to terminal No. 4. See STEP 2 in (Scheme 3). Check for continuity between charge light relay terminals No. 1 and 2. If relay does not test as indicated, replace relay.

ENGINE MAIN RELAY TEST (CAMRY, CELICA, COROLLA, TERCEL)

1. Using an ohmmeter, check for continuity between engine main relay terminals No. 3 and 5 and between terminals No. 1 and 2. Ensure continuity does not exist between terminals No. 3 and 4. See STEP 1 in (Scheme 4). If engine main relay does not test as indicated, replace relay. For location of engine main relay, see «ENGINE MAIN RELAY LOCATION»(/toyota/4runner/ii-1987-1995/remont/charging-system/#alternator-regulator) table.
2. Check engine main relay operation. Apply battery voltage between terminals No. 1 and 2. Using an ohmmeter, check that continuity exists between terminals No. 3 and 4. Ensure continuity does not exist between terminals No. 3 and 5. See STEP 2 in (Scheme 4). If main relay does not test as indicated, replace relay.

ENGINE MAIN RELAY LOCATION

IGNITION RELAY TEST (LAND CRUISER)

1. Using an ohmmeter, check for continuity between ignition relay terminals No. 1 and 3. Ensure continuity does not exist between terminals No. 2 and 4. See STEP 1 in (Scheme 5).
2. Ensure continuity does not exists between terminals No. 3 and 4. If ignition relay does not test as indicated, replace relay. NOTE: Ignition relay is located in relay box, above left kick panel.
3. Check ignition relay operation. Apply battery voltage across terminals No. 1 and 3. Using an ohmmeter, check that continuity exists between terminals No. 2 and 4. See STEP 2 in (Scheme 5).
4. Ensure continuity does not exists between terminals No. 3 and 4. If ignition relay does not test as indicated, replace relay.

Scheme 4

Scheme 5

BRUSHES

1. Check for cracks and minimum brush length of .18-.22" (4.5-5.5 mm). Replace brushes if damaged or worn. Brushes should slide smoothly in holders. Install new springs when replacing brushes. Solder brush wire.
2. New brush exposed length should be .413" (10.5 mm). Old brush minimum exposed length not be less than .059" (1.5 mm).

ROTOR

1. Check rotor for open field windings by using an ohmmeter across slip rings. Rotor resistance should be 2.8-3.0 ohms.
2. Check rotor for shorts to ground by connecting ohmmeter between slip ring and rotor shaft. Ohmmeter should indicate no continuity. Check slip rings for wear or pitting.
3. Turn slip rings on lathe if necessary. Minimum slip ring diameter is .504" (12.8 mm). Check bearing and replace if necessary.

STATOR

Connect ohmmeter between 2 stator leads. Continuity should exist between all stator leads. Connect ohmmeter between each stator lead and metal core. Continuity should not exist. If stator does not test as indicated, replace stator.

DIODES

1. With diode 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 for all diodes.
2. All diodes should show a low reading in one direction and NO reading in opposite direction. If any diode is defective, replace diode assembly.

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL INFORMATION section.

OVERHAUL

Note. Overhaul procedures are not available from manufacturer. (Scheme 6)through (Scheme 15) for views of alternator assembly.

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• ALTERNATOR OUTPUT SPECIFICATIONS