GM Service Manual Online
For 1990-2009 cars only

Charging System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Move the ignition switch from the OFF position to the RUN position.

Battery indicator lamp turns ON, voltmeter gage reads between 12-14 volts.

    • Refer to Indicator - Charge Inoperative.
    • Refer to Guage - Voltmeter Inaccurate or Inoperative

2

Move the Ignition Switch to the START position and then release.

The engine starts, the voltage gage reads between 13-16 volts, the battery indicator lamp turns OFF.

Refer to Indicator - Charge Always On.

3

Run the engine at idle while observing the voltmeter gage and the battery indicator lamp.

Voltmeter gage holdssteady between 13-16 volts and the battery indicator lamp is OFF.

Refer to Generator Electrical Test.

4

  1. Turn on the following electrical components:
  2. • Headlamps
    • Rear defogger
    • Heater blower motor to HI
  3. Increase the engine speed to 2500 RPM for 2 minutes and observe the voltmeter gage.

Voltmeter gage holds steady between 13-16 volts and the battery indicator lamp is OFF.

Refer to Generator Electrical Test.

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