Tools Required
GM P/N 12303040 Battery Side Terminal Adapters
- If the battery has not been load tested yet, 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. If not, replace the battery.
- Install battery side terminal adapters.
- Connect a voltmeter and a battery lead tester across the battery terminals.
- 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, then apply the specified load from the specifications. Read the voltage after 15 seconds, then turn off the load.
- If 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 Temperature Versus Voltage Drop .
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.
Vehicle Related Conditions
After the battery has been charged or tested and has proven to be a good battery, the cause of the no-start or slow cranking condition must be determined to prevent comebacks. If no obvious cause is evident, the vehicles electrical system should be diagnosed using the following steps:
| • | If the battery has passed a load test and the engine still will not turn over or is difficult to start, the cranking system should be checked. |
| • | If the cranking system test reveals no abnormal conditions, but excessive cranking is required to start the vehicle, the cause must be diagnosed and corrected to reduce battery demands. Two possible causes for excessively long cranks are fuel or ignition system problems. |
| • | If the battery discharges while the vehicle sits for a few hours or days, the vehicle should be diagnosed for parasitic loads. Simple connection of an ammeter in series with the battery may not find the cause as the condition may not show up when power is restored unless that particular component is repeatedly cycled. Refer to Parasitic Load Test. |
| • | If a battery becomes discharged and no excessive current drain is found, the operation of the charging system should be checked. |
Driver Related Conditions
If no cause is found for a discharged battery and the battery tests good, a light may have been left on; or the driving habits of the owner may be such that, especially with many short trips and repeated starts, the generator does not get a chance to recharge the battery between starts.
