DIAGNOSE – BATTERY DIES DURING START ATTEMPT
The battery goes dead or will not start the vehicle. The engine may crank slowly for a short period then fail to crank over.
The battery provides the necessary energy to start the vehicle. The ignition switch will route power from the battery to the starter motor to crank the engine. Once the engine is started, the alternator will re-charge the battery and provide the necessary electrical power to operate the vehicle’s electrical system. If the alternator is defective, the battery will not recharge once the engine is started. If there is an electrical load that is on such as a glove box or courtesy light that remains on at all times, this will also drain the battery over an extended period of time. Batteries can also fail internally which can cause them to self discharge.
If the engine can be started via a jump start and the battery light comes on, you should suspect a failure in the charging system. You should refer to the article “Battery Light On” on this website for diagnosis of this symptom. It will be necessary to determine whether the battery is defective or there is some electrical load on the battery causing it to drain over an extended period of time. Most repair shops or part stores can charge and test the battery for a nominal fee. This should be the first step in the diagnosis. You should also inspect for electrical loads that are present even after the vehicle is shut off. The hood, trunk, and glove box lamp should be inspected to ensure they are off when the corresponding door is closed. Temporarily removing the bulb to determine if the symptom is eliminated can isolate which circuit is the cause.