Hummer H3. Manual — part 1135

5

3. Connect a carbon pile tester

to the vehicle.

4. Connect an inductive

ammeter probe to the output
circuit of the generator.

5. Start the engine.

6. With a scan tool, command

the GEN-L Terminal ON.

7. Increase engine speed to

2,500 RPM.

8. Adjust the carbon pile, as

necessary, in order to obtain
the maximum current
output.

Is the generator output greater
than or equal to the load test
value as specified in Generator
Usage ?

violently.

IMPORTANT:

When measuring generator
output current, be sure the
inductive probe encircles the
generator output wire.

-

System OK

Go to Step 7

6

Is the voltage measured greater
than 15.5 volts?

-

Go to Step

12

Go to Step 7

7

1. Leave the vehicle

accessories ON or maintain
load test value.

2. Maintain engine speed at

2,500 RPM.

3. Measure the voltage

between the generator
output terminal and the
generator metal housing.

B+

2007 Hummer H3

2007 ENGINE Engine Electrical - H3

Is the voltage measured equal to
the specified value?

Go to Step

14

Go to Step 9

8

1. Turn ON the ignition, with

the engine OFF.

2. Disconnect the generator

harness connector.

3. Measure the voltage

between the generator turn
ON signal circuit and
ground.

4. Start the engine.

5. With a scan tool, command

the GEN-L Terminal ON
and OFF.

Does the voltage measure greater
than the first value ON and near
the second value OFF?

4.7 V

0 V

Go to Step

14

Go to Step 11

9

1. Maintain the engine speed

at 2,500 RPM and continue
to operate the generator at
the load test value.

2. Measure the voltage drop

from the battery negative
terminal to the metal
housing of the generator.
Refer to Circuit Testing
and Wiring Repairs .

Is the voltage measured less than
the specified value?

0.5 V

Go to Step

10

Go to Step 15

1. Maintain the engine speed

at 2,500 RPM and continue
to operate the generator at
the load test value.

2. Measure the voltage drop

from the output terminal of

2007 Hummer H3

2007 ENGINE Engine Electrical - H3

10

the generator to the positive
terminal on the battery.
Refer to Circuit Testing
and Wiring Repairs .

Is the voltage measured less than
the specified value?

0.5 V

Go to Step

14

Go to Step 16

11

Test the generator turn on signal
circuit for a short or open. Refer
to Circuit Testing and Wiring
Repairs .
Did you find and correct the
condition?

-

Go to Step

19

Go to Step 13

12

Test the generator battery voltage
sense circuit, if equipped, for an
open or high resistance. Refer to
Circuit Testing and Wiring
Repairs .
Did you find and correct the
condition?

-

Go to Step

19

Go to Step 14

13

Inspect for poor connections at
the harness connector of the
powertrain control module
(PCM). Refer to Testing for
Intermittent Conditions and
Poor Connections and
Connector Repairs .
Did you find and correct the
condition?

-

Go to Step

19

Go to Step 17

14

Inspect for poor connections at
the generator. Refer to Testing
for Intermittent Conditions
and Poor Connections and
Connector Repairs .
Did you find and correct the
condition?

-

Go to Step

19

Go to Step 18

15

Repair the high resistance or
open in the ground circuit of the
generator. Refer to Wiring

-

-

2007 Hummer H3

2007 ENGINE Engine Electrical - H3

CHARGE INDICATOR ALWAYS ON

Charge Indicator Always On

Repairs .
Did you complete the repair?

Go to Step

19

16

Repair the high resistance or
open in the generator output
circuit. Refer to Wiring
Repairs .
Did you complete the repair?

-

Go to Step

19

-

17

Replace the PCM. Refer to
Control Module References for
replacement, setup and
programming.
Did you complete the
replacement?

-

Go to Step

19

-

18

Replace the generator. Refer to
Generator Replacement.
Did you complete the
replacement?

-

Go to Step

19

-

19

Operate the vehicle in order to
verify the repair.
Did you correct the condition?

-

System OK

Go to Step 2

Step

Action

Value(s)

Yes

No

Schematic Reference: Starting and Charging Schematics or Instrument Cluster
Schematics

1

Did you perform the Diagnostic
System Check - Vehicle?

-

Go to Step 2

Go to
Diagnostic
System Check
- Vehicle

2

Start the engine.
Does the battery charge indicator
remain illuminated?

-

Go to Step 3

Go to Testing
for
Intermittent
Conditions
and Poor
Connections

1. Install a scan tool

2007 Hummer H3

2007 ENGINE Engine Electrical - H3