GM Service Manual Online
For 1990-2009 cars only

Caution: Refer to Batteries Produce Explosive Gases Caution in the Preface section.

The sealed battery is standard on all cars. There are no vent plugs in the cover. The battery is completely sealed, except for 2 small vent holes in the sides. These vent holes allow the small amount of gas produced in the battery to escape. The battery has the following advantages over conventional batteries:

    • No water addition for the life of the battery
    • Overcharge protection--If too much voltage is applied to the battery, it will not accept as much current as a conventional battery. In a conventional battery, the excess voltage will still try to charge the battery, leading to gassing, which causes liquid loss.
    • Not as liable to self-discharge as a conventional battery--This is particularly important when a battery is left standing for long periods of time.
    • More power available in a lighter, smaller case

The battery has 3 major functions in the electrical system. First, the battery provides a source of energy for cranking the engine. Second, the battery acts as a voltage stabilizer for the electrical system. Finally, the battery can, for a limited time, provide energy when the electrical demand exceeds the output of the generator.

Ratings

    • Reserved Capacity Rating--The time a fully charged battery will provide 25 amperes of current flow at or above 10.5 volts. A reserve capacity rating is designated at 27°C (80°F).
    • Cold Cranking Amp Rating--Indicates cranking load capacity. Cold cranking amp rating is determined under testing at a temperature of -18°C (0°F).

Reserve Capacity

The reserve capacity (RC) is the maximum length of time it is possible to travel at night with the minimum electrical load and no generator output. Expressed in minutes, the RC rating is the time required for a fully charged battery, at a temperature of 27°C (80°F) and being discharged at a current of 25 amperes, to reach a terminal voltage of 10.5 volts.

Cold Cranking Amperage

The cold cranking amperage test is expressed at a battery temperature of -18°C (0°F). The current rating is the minimum amperage, which must be maintained by the battery for 30 seconds at the specified temperature, while meeting a minimum voltage requirement of 7.2 volts, This rating is a measure of cold cranking capacity.

The battery is not designed to last indefinitely. However, with proper car, the battery will provide many years of service.

If the battery test well, but fails to perform satisfactorily in service for no apparent reason, the following factors may point to the cause of the trouble:

    • Vehicle accessories are left on overnight.
    • Slow average driving speeds are used for short periods.
    • The vehicle electrical load is more than the generator output, particularly with the addition of aftermarket equipment.
    • Defects in the charging system, such as electrical shots, a slipping generator belt, a faulty generator, or a faulty voltage regulator
    • Battery abuse, including failure to keep the battery cable terminal clean and tight, or a loose battery hold-down clamp
    • Mechanical problems in the electrical system, such as shorted or pinched wires

Built-In Hydrometer

The sealed battery has a built-in, temperature-compensated hydrometer in the top of the battery. This hydrometer is to be used with the following diagnostic procedure:

  1. When observing the hydrometer, make sure that the battery has a clean top.
  2. Under normal operation, 2 indication can be observed:
  3. • Green Dot Visible--Any green appearance is interpreted as a green dot, meaning the battery is ready for testing.
    • Dark Green Dot Is Not Visible--If there is a cranking complaint, the battery should be tested. The charging and electrical systems should also be checked at this time.
  4. Occasionally, a third condition may appear:
  5. Clear or Bright Yellow--This means the fluid level is below the bottom of the hydrometer. This may have been caused by excessive or prolonged charging, a broken case, excessive tipping, or normal battery wear. Finding a battery in this condition may indicate high charging by a faulty charging system. Therefore, the charging and the electrical systems may need to be checked if a cranking complaint exists. If the cranking complaint is caused by the battery, replace the battery.

Charging Procedure

  1. Batteries with the green dot showing do not require charging unless they have just been discharged, such as in cranking a vehicle.
  2. When charging sealed-terminal batteries out of the vehicle, install the adapter kit. Make sure all the charger connections are clean and tight. For best results, batteries should be charged while the electrolyte and the plates are at room temperature. A battery that is extremely cold may not accept current for several hours after starting the charger.
  3. Charge the battery until the green dot appears. The battery should be checked every half-hour while charging. Tipping or shaking the battery may be necessary to make the green dot appear.
  4. After charging, the battery should be load tested. Refer to Battery Inspection/Test .

Charging Time Required

The time required to charge a battery will vary depending upon the following factors:

Size of Battery: A completely discharged large heavy-duty battery requires more than twice the recharging time as a completely discharged small passenger car battery.

Temperature: A longer time will be needed to charge any battery at -18°C (0°F) than at 27°C (80°F). When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first. The battery will accept a higher current rate as the battery warms.

Charger Capacity: A charger which can supply only 5 amperes will require a much longer charging period than a charger that can supply 30 amperes or more.

State-of-Charge: A completely discharged battery requires more than twice as much charge as a one-half charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the current accepted by the battery is very low at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current will likewise increase.

Charging a Completely Discharged Battery (Off the Vehicle)

Unless this procedure is properly followed, a perfectly good battery may be needlessly replaced.

The following procedure should be used to recharge a completely discharged battery:

  1. Measure the voltage at the battery terminals with an accurate voltmeter. If the reading is below 10 volts, the charge current will be very low, and it could take some time before the battery accepts the current in excess of a few milliamperes. Refer to Charging Time Required, which focuses on the factors affecting both the charging time required. Such low current may not be detectable on ammeters available in the field.
  2. Set the battery charger on the high setting.
  3. Important: Some chargers feature polarity protection circuitry, which prevents charging unless the charge leads are correctly connected to the battery terminals. A completely discharged battery may not have enough voltage to activate this circuity, even though the leads are connected properly, making it appear that the battery will not accept charging current. Therefore, follow the specific charger manufacturer's instruction for bypassing or overriding the circuitry so that the charger will turn on and charge a low-voltage battery.

  4. Continue to charge the battery until the charge current is measurable. Battery chargers vary in the amount of voltage and current provided. The time required for the battery to accept a measurable charger current at various voltages may be as follows:

Voltage

Hours

16.0 or more

Up to 4 hours

14.0-15.9

Up to 8 hours

13.9 or less

Up to 16 hours

    • If the charge current is not measurable at the end of the above charging times, the battery should be replaced.
    • If the charge current is measurable during the charging time, the battery is good, and charging should be completed in the normal manner.

       Important: It is important to remember that a completely discharged battery must be recharged for a sufficient number of ampere hours (AH) to restore the battery to a usable state. As a general rule, using the reserve capacity rating (RC) as the number of ampere hours of charge usually brings the green dot into view.

    • If the charge current is still not measurable after using the charging time calculated by the above method, the battery should be replaced.

Jump Starting Procedure

    Notice: Refer to Ignition OFF When Disconnecting Battery Notice in the Preface section.

  1. Position the vehicle with the charged battery so that the jumper cables will reach from the charged battery to the battery that requires charging.
  2. Turn off the ignition, all the lights, and all the electrical loads in both vehicles.
  3. Leave the hazard flasher on if jump starting where there may be other traffic and any other lights needed for the work area.
  4. Apply the parking brake firmly in both vehicles.
  5. Notice: Route the accelerator cable through the groove in throttle body lever. Securely seat the accelerator cable.

  6. Shift an automatic transmission to PARK, or a manual transmission to NEUTRAL.
  7. Caution: Cables that have missing or loose insulation should be replaced. Failure to properly maintain cables could result in personal injury or vehicle damage.

  8. Clamp one end of the first jumper cable to the positive terminal on the booster battery. Make sure it does not touch any other metal parts.
  9. Clamp the other end of the same cable to the positive terminal on the discharged battery. Never connect the other end to the negative terminal of the discharged battery.
  10. Caution: Do not connect a jumper cable directly to the negative terminal of a discharged battery to prevent sparking and possible explosion of battery gases.

  11. Clamp one end of the second cable to the negative terminal of the booster battery.
  12. Make the final connection to a solid engine ground, such as the engine lift bracket at least 450 millimeters (18 in) from the discharged battery.
  13. Start the engine of the vehicle with the good battery. Run the engine at a moderate speed for several minutes.
  14. Then start the engine of the vehicle with the discharged battery.
  15. Remove the jumper cables by reversing the above sequence exactly, removing the negative cable from the vehicle with the discharged battery first. While removing each clamp, take care that it does not touch any other metal while the other end remains attached.

Generator

The Delco-Remy CS charging system has several models available, including the CS-128D (2.0L) and the CS-121DIF (2.5L). The number denotes the outer diameter in millimeters of the stator lamination.

CS generators are equipped with internal regulators.

Unlike three-wire generators, the CS-128D or the CS-121DIF may be used with only 2 connections: battery positive and an L terminal to the charge indicator lamp.

As with other charging systems, the charge indicator lamp lights when the ignition switch is turned to RUN, and goes out when the engine is running. If the charge indicator is on with the engine running, a charging system defect is indicated. This indicator light will glow at full brilliance for several kinds of defects as well as when the system voltage is too high or too low.

The regulator voltage setting varies with temperature and limits the system voltage by controlling rotor field current. Achieve correct average field current for proper system voltage control by varying the on-off time. At high speeds, the on-time may be 10 percent and the off-time 90 percent. At low speeds, with high electrical loads, the on-time may be 90 percent and the off-time 10 percent.

Starter

Wound field starter motors have pole pieces, arranged around the armature, which are energized by wound field coils.

Enclosed shift lever cranking motors have the shift lever mechanism and the solenoid plunger enclosed in the drive housing, protecting them from exposure to dirt, icy conditions, and splashes.

In the basic circuit, solenoid windings are energized when the switch is closed. The resulting plunger and shift lever movement causes the pinion to engage the engine flywheel ring gear. The solenoid main contacts close. Cranking then takes place.

When the engine starts, pinion overrun protects the armature from excessive speed until the switch is opened, at which time the return spring causes the pinion to disengage. To prevent excessive overrun, the switch should be released immediately after the engine starts.