Battery Load Test Diagnosis

Visual Inspection

1. Before performing the load test, visually inspect the battery for obvious damage, such as a cracked or broken case.
2. Repair the cause of any damage or replace the battery. Refer to Battery Replacement.

Hydrometer Check

1. If the green dot is visible (A), perform the load test. Refer to Battery Load Test .
2. If the green dot is not visible (B), charge the battery. Refer to Battery Charging .
3. If the dot is clear or yellow (C), replace the battery. Refer to Battery Replacement .

Battery Load Test Test

Tools Required

GM P/N 12303040 Battery Side Terminal Adapters

Important: Do not load test a frozen battery. Replace it instead.

1. Use a voltmeter in order to check the voltage across the battery terminals. If the green dot is visible, the voltage should be 12 volts or above. Unless the battery has just been discharged (such as, by load testing or cranking the engine), replace the battery if the voltage is below 12 volts.



2. Install battery side terminal adapters.
3. Connect a voltmeter and a battery lead tester across the battery terminals.

Important: Do not complete this step if the battery has not been recently charged.

4. If the battery has been charging, apply a 300 ampere load for 15 seconds in order to remove the surface charge from the battery. Remove the load.
5. Wait 15 seconds in order to let the battery recover, then apply the specified load from the specifications. Read the voltage after 15 seconds, then turn off the load.

Important: The battery temperature must be estimated by the feel and by the temperature the battery has been exposed to for the preceding few hours.

6. When the voltage does not drop below the minimum voltage, the battery is good and should be returned to service. If the voltage is less than the minimum, replace the battery. Refer to Battery Voltage vs Temperature .