Tools Required

1. Before performing the load test, visually inspect the battery for obvious damage, such as a cracked or broken case. If the battery is damaged, replace the battery. Refer to Battery Replacement .
2. Load testing requires the battery to be in a fully charged state in order to obtain an accurate test. When load testing the battery out of the vehicle use GM P/N 12303040 to ensure good connections.
3. With the load in the tester turned OFF, connect a corbon pile load tester and the J 39200 across the battery terminals. With all loads off and the green dot showing in the hydrometer, the voltage should be 12 V or higher. Unless the battery has just been discharged (such as by a load test or cranking the engine), replace the battery if the voltage is below 12 V. Refer to Battery Replacement .
4. With the J 39200 still attached, connect a battery load tester across the battery terminals.

Important: Do not remove the surface charge from the batteries that have been in storage.

5. If the battery has been charged recently, apply a 300 ampere load for 15 seconds in order to remove the surface charge from the battery. Remove the load. Wait 15 seconds in order to let the battery recover.
6. The battery temperature must be estimated by touch and also by the temperature the battery has been exposed to during the preceding few hours. Refer to Battery Temperature Versus Minimum Voltage .
7. Apply the specified load located on the battery label or listed in the battery specifications table. Refer to Battery Usage .
8. Read the voltage after 15 seconds. Then remove the load.
9. If the voltage drops below the minimum value listed, replace the battery. Refer to Battery Replacement .
10. If the voltage does not drop below the minimum value, the battery is good and should be returned to service.