GM Service Manual Online
For 1990-2009 cars only

On Vehicle Inspection Procedure

Tools Required

J 39200 Digital Multimeter

On vehicles equipped with a charge indicator, when the charging system is operating normally, the charge indicator goes on when the ignition switch is ON, and will go out when the engine is running. If the lamp remains on with the engine running, the battery may be under- or overcharged. Battery voltage should be between 11 and 16 Volts.

On vehicles equipped with a voltmeter, when the charging system is operating normally, the voltmeter will read between 11 and 16 Volts.

In order to diagnose the cause of an undercharged battery. Observe the following precautions before diagnosing the charging system. Failure to follow these precautions may lead to electrical equipment damage:

Precautions

  1. Do not reverse the connections to the generator.
  2. Do not short across or ground any of the terminals, unless otherwise directed.
  3. Never disconnect the BAT terminal while the generator is operating.
  4. When connecting a charger or a booster battery, follow the procedure in Jump Starting in Case of Emergency .
  5. Do not attempt to disassemble the CS-130 generator. Damage to the generator could result.

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

  1. Abnormal charge indicator operation
  2. An abnormal voltmeter reading
  3. An undercharged battery condition (with slow cranking or a dark hydrometer)
  4. An overcharged battery condition (with electrolyte leaks or a yellow hydrometer). Refer to Battery Replacement .

Diagnosis

In order to diagnosis the charging system, use the following procedure.

  1. Inspect the accessory drive belt for damage or wear. Service or replace as necessary.
  2. Inspect the wiring.
  3. Refer to GEN Light Off w/ Ign in Run Position, Engine Off or an abnormal charge indicator lamp operation.
  4. For an undercharged or overcharged battery condition, refer to Battery Is Undercharged or Overcharged .