Battery Load Test

^ Load testing requires the use of battery side terminal adapters, GM P/N 12303040 or equivalent to ensure good connections. Do not load test a frozen battery. Replace it instead.
A. Use J 39200 digital multimeter to measure voltage across the terminals. With all loads off, and the green dot showing in the hydrometer, voltage should be 12 volts or higher. Unless the battery has just been discharged (such as by load test or cranking the engine), replace the battery if the voltage is below 12 volts.
B. With J 39200 still attached, connect a battery load tester across the battery terminals.
C. If the battery has been charging, apply a 300 ampere load for 15 seconds to remove the surface charge from the battery. Remove the load. (Do not complete this step if the battery has not been recently charged.)
D. Wait 15 seconds to let the battery recover. Apply the specified load located on the battery label or listed in "Specifications". Read the voltage after 15 seconds, then remove the load.
E. If the voltage does not drop below the minimum value listed, the battery is good and should be returned to service. (The battery temperature must be estimated by feel and by the temperature the battery has been exposed to for the proceeding few hours.)
F. If voltage drops below the minimum value listed, replace the battery.

ESTIMATED TEMPERATURE MINIMUM VOLTAGE
70°F (21°C) 9.6
50°F (10°C) 9.4
30°F (0°C) 9.1
15°F (-10°C) 8.8
0° F (10°C) 8.5
0° F (BELOW -18°C) 8.0