GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Check the generator pulley drive belt tension.

The drive belt is correctly tensioned.

    •  Drive Belt Tensioner Diagnosis 4.3 L in Engine Mechanical
    •  Drive Belt Tensioner Diagnosis 5.0,5.7 L in Engine Mechanical
    •  Drive Belt Tensioner Diagnosis 6.5 L in Engine Mechanical
    •  Drive Belt Tensioner Diagnosis 7.4 L in Engine Mechanical

2

Visually inspect the battery for physical damage.

The battery case is not cracked or broken.

Battery Replacement

3

Inspect the battery terminal connections.

The battery terminals are clean and tight.

Fastener Tightening Specifications or Battery Cable Replacement

4

Visually inspect the built-in battery hydrometer.

The battery hydrometer displays a green dot.

Battery Hydrometer Displays Dark or Yellow Dot

5

Inspect the generator output terminal for a loose connection.

The generator output terminal is clean and tight.

Fastener Tightening Specifications

6

Inspect the generator 4-way connector for looseness or damaged terminals.

Each terminal in the generator 4-way connector will firmly hold a Metri-Pack 150 terminal adapter from J 35616 Connector Test Adapter Kit.

Connector Repairs

7

Battery Not Operating Properly

The battery passes the load test.

Battery Replacement

8

Generator Not Operating Properly

The generator passes the electrical test.

Generator Replacement

9

Start the engine and allow it to idle.

The volts gauge in the instrument cluster is in the normal range.

Voltmeter Displaying High or Low

10

Increase the engine speed to 2500  RPM.

The volts gauge in the instrument cluster is in the normal range.

Voltmeter Displaying High or Low

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.