Suzuki Grand Vitara JB416 / JB420. Manual - part 136

1J-2 Charging System: 

• Green Dot:

Battery is sufficiently charged for testing.

• Dark:

Battery must be charged before testing.
If there is a cranking complaint, battery should be tested as described in “Battery Inspection”.
Charging and electrical systems should also be checked at this time.

• Clear or Light Yellow:

This means that fluid level is below the bottom of hydrometer. Its possible cause is excessive or prolonged 
charging, a broken case, excessive tipping or normal battery deterioration.
When the battery is found in such condition, it is possible that high charging voltage is caused by the faulty charging 
system and therefore, charging and electrical systems need to be checked. If there is a trouble in cranking and its 
cause lies in the battery, it should be replaced.

Generator Description

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The basic charging system is the IC integral regulator charging system. The internal components are connected 
electrically as shown below.

Diagnosis

OK

Charging necessary Low Level Electrolyte Replace Battery

Indicator

Green dot

Dark

Clear

Gravity Ball

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IYSQ011A0066-01

IYSQ011A0067-01

IYSQ011A0068-01

IYSQ011A0069-01

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1. Pulley

6. Field coil

11. Rear housing

IG: Ignition terminal

2. Pulley nut

7. Rectifier

B: Generator output (Battery terminal)

L: Lamp terminal

3. Rotor fan

8. Brush

C: Generator cut 

4. Stator coil

9. Regulator

E: Ground

5. Stator core

10. Front housing

FR: Field duty monitor

Charging System:  1J-3

Charging System Circuit
The generator features a solid state regulator that is mounted inside the generator. All regulator components are 
enclosed into a solid mold, and this unit along with the brush holder assembly is attached to the rear housing. The 
regulator voltage is being controlled by ECM under some conditions while driving. Refer to “Generator Control System 
Description in Section 1A”.
The generator rotor bearings contain enough grease to eliminate the need for periodic lubrication.
Two brushes carry current through the two slip rings to the field coil mounted on the rotor, and under normal conditions 
will provide long period of attention-free service.
The stator windings are assembled inside a laminated core that forms part of the generator frame.
A rectifier bridge connected to the stator windings contains diodes, and electrically changes the stator AC. voltages to 
a D.C. voltage which appears at the generator output terminal.

Diagnostic Information and Procedures

Battery Inspection

S5JB0A1A04004

Common Causes of Failure
A battery is not designed to last indefinitely; however, with proper care, it will provide many years of service. If the 
battery performs satisfactorily during test but fails to operate properly for no apparent reason, the following are some 
factors that may point to the cause of trouble:
• Accessories left on overnight or for an extended period without the generator operating.
• Slow average driving speeds for short periods.
• Electrical load exceeding generator output particularly with addition of aftermarket equipment.
• Defects in charging system such as high resistance, slipping drive belt, loose generator output terminal, faulty 

generator or voltage regulator. Refer to “Generator Symptom Diagnosis”.

• Battery abuse, including failure to keep battery cable terminals clean and tight or loose battery hold down.
• Mechanical problems in electrical system such as shorted or pinched wires.

Visual inspection
Check for obvious damage, such as cracked or broken case or cover, that could permit loss of electrolyte.
If obvious damage is noted, replace battery. Determine cause of damage and correct as needed.

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1. Generator with regulator assembly

4. Diode

7. Main switch

2. I.C. regulator

5. Field coil (rotor coil)

8. Battery

3. Stator coil

6. Charge indicator light

9. ECM

1J-4 Charging System: 

Generator Symptom Diagnosis

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A charging circuit wiring diagram for generator connection is shown in “Generator Description”. To avoid damage, 
always follow these precautions:

CAUTION

!

 

• Do not mistake polarities of “IG” terminal and “L” terminal.
• Do not create a short circuit between “IG” and “L” terminals. Always connect these terminals 

through a lamp.

• Do not connect any load between “L” and “E” terminals.
• When connecting charger or booster battery to vehicle battery, refer to “Jump Starting in Case of 

Emergency”.

 

Trouble in charging system will show up as one or more of the following conditions:

1) Faulty charge indicator light operation.
2) An undercharged battery as evidenced by slow cranking or indicator clear with dark on light yellow dot.
3) An overcharged battery as evidenced by excessive spewing of electrolyte from vents.

Generator Test (Undercharged Battery Check)

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This condition, as evidenced by slow cranking or 
indicator clear with dark or light yellow dot can be 
caused by one or more of the following conditions even 
though indicator lamp may be operating normal.
The following procedure also applies to cars 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.
3) If battery defect is suspected, refer to “Battery 

Description”.

4) Inspect wiring for defects. Check all connections for 

tightness and cleanliness, battery cable connections 
at battery, starting motor, ignition ground cable and 
no “C” terminal circuit at ground.

5) Connect switch (6), load (5), battery (4), voltmeter 

(3) and ammeter (2) to generator (1) as shown in 
figure.

Voltmeter: Set between generator “B” terminal 
and ground.
Ammeter: Set between generator “B” terminal 
and battery (+) terminal.

NOTE
Use fully charged battery.

 

6) Measure current and voltage.

Condition

Possible cause

Correction / Reference Item

Noisy generator

Loose drive belt

Adjust or replace drive belt.

Loose drive belt pulley

Check generator.

Loose mounting bolts

Check mounting condition.

Worn or dirty bearings

Check generator.

Defective diode or stator

Check generator.

Charge indicator light 
does not light with 
ignition ON and engine off

Fuse blown

Check fuse.

Indicator lamp (LED) faulty

Check BCM, combination meter and/or CAN 
communication line.

Wiring connection loose

Tighten loose connection.

IC regulator faulty

Check generator.

Poor contact between brush and slip 
ring

Repair or replace.

Charge indicator light 
does not go out with 
engine running
Battery requires frequent 
recharging

Drive belt loose or worn

Adjust or replace drive belt.

IC regulator or generator faulty

Check charging system.

Wiring faulty

Repair wiring.

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Charging System:  1J-5

No-Load Check

1) Run engine from idling up to 2000 rpm and read 

meters.

NOTE
Turn off switches of all accessories (wiper, 
heater etc.).

 

Specification for undercharged battery (No-load 
check)
Current: 10 A
Voltage: 14.2 – 14.8 V (at 20 

°C, 68 °F)

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

 

2) Using service wire, ground “C” terminal (1) of 

generator.

3) Measure voltage between “B” terminal of generator 

and body ground.

Voltage: 12.5 – 13.1 V (at 20 

°C, 68 °F)

• If voltage is higher than standard value

If voltage is higher than standard value, check ground 
of brushes.
If brushes are not grounded, replace IC regulator.
If voltage is lower than standard value, proceed to the 
following check.

Load Check

1) Run engine at 2000 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 (Overcharged Battery Check)

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1) To determine battery condition, refer to “Battery 

Description”.

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 disassemble generator.

4) Check ground of brushes. If brushes are not 

grounded, replace IC regulator. Then check field coil 
for grounds and shorts, referring to “Generator 
Inspection”.

[A]: Regulated voltage (V)
[B]: Heat sink temperature (

°C)

16.0

15.5

14.3

15.2

14.8

14.2

13.3

14.6

15.0

14.5

14.0

13.5

13.0

-30

0

20

[A]

[B]

68

 22

120 (˚C)

248 (˚F)

(V)

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[A]: Regulated voltage (V)
[B]: Heat sink temperature (

°C)

16.0

15.5

14.3

15.2

14.8

14.2

13.3

14.6

15.0

14.5

14.0

13.5

13.0

-30

0

20

[A]

[B]

68

 22

120 (˚C)

248 (˚F)

(V)

I5JB0A1A0006-02