GM Service Manual Online
For 1990-2009 cars only

Charge Indicator Always On W/O (GBCM)

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Start the engine.

Does the battery charge indicator remain illuminated after the 5-second bulb check?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

3

  1. Install a scan tool.
  2. With a scan tool, observe the Battery Voltage parameter in the instrument panel cluster (IPC) data list.

Does the voltage measure within the normal operating range?

10-15 V

Go to Step 4

Go to Charging System Test

4

Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 5

--

5

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

Charge Indicator Always On W/ (GBCM)

Diagnostic Aids (Diesel Engine Only)

When starting a cold engine, glow plug cycle time can last 18 seconds with an after glow time of 30 seconds depending on engine temperature. Average glow plug amperage draw is 130 amps. The intake air heater may draw as high as 45 amps. Due to these high current draws the battery indicator may remain on until the amperage draw is reduced.

Step

Action

Values

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Start the engine.
  2. Turn OFF all accessories.

Does the battery charge indicator remain illuminated?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Install a scan tool.
  2. Start the engine.
  3. Turn OFF all accessories.
  4. Increase engine speed to 1,500 RPM.
  5. With a scan tool, observe the Battery Voltage parameter in the generator battery control module (GBCM) ,body control module (BCM) data list, engine control module (ECM) and the instrument panel cluster (IPC) data list.
  6. Compare the voltages.

Are all of the voltages within the specified range?

0.9-1.1 V

Go to Step 4

Go to Step 5

4

Are the voltages displayed within the specified range?

12.8-15.5 V

Go to Step 5

Go to Charging System Test

5

Test the battery positive voltage and ground circuits of the affected module for a high resistance or open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 6

6

Inspect for poor connections at the harness connector of the affected module. Refer to Connector Repairs .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

7

Replace the affected module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2