Wiki User
∙ 2012-08-04 17:47:35Disconnect the negative cable.
Wiki User
∙ 2012-08-04 17:47:35Possibly a bad alternator. The Alternator charges the battery when the vehicle is running. If the battery is not being charged this could cause the vehicle not to start.
Best to unplug it and then disconnect it from the battery. Reason being is that if you disconnect it from the battery first you will create a spark. That spark could ignite any fumes from the battery.
From your description it sounds as if the warning light is operating correctly. When the engine is running the battery is being charged and the electrical needs of the vehicle are being fully met by the alternator's output and the battery is not expending stored power. When you turn the engine off the alternator stops running and anything in the vehicle that requires electircal power is suddenly dependent upon the battery to supply it. Thus, the battery begins discharging power, which triggers the warning light indicating that the battery is being discharged.
Ignition off, hook a battery charger to the battery post and let it charge. Black - Red + Disconnect the charger before starting the vehicle. You do not have to remove the cables nor take the battery out of the vehicle. Batteries are constantly being charged on the vehicle with the alternator. That is just unnecessary work for nothing. Since the battery is in the fender, you hook the battery charger to the jump start posts under the hood.
Your alternator has failed, and the battery has drained from running the vehicle without being able to recharge it. Replace the alternator and the battery should be fine.
This could be because you didn't disconnect it before you started pulling it.When you tow a vehicle, you should turn the key to 'on' so that the wheel can turn to allow the vehicle to follow the lead vehicle.
If your engine is running , and the battery light comes on , that indicates that your battery is not being charged
unhook battery
First of all - tHe engine will stop as soon as you disconnect the battery. Secondly - you risk being electrocuted if you do that !
If your alternator stops working you are powering the vehicle on your battery and your battery is not being charged by your faulty alternator so eventually as the battery drains down the car will stop running. Avoid using any electrical power...ie...lights, power windows ect and get your alternator repaired immediatley.
Something is causing a drain on the battery even with the vehicle off and nothing turned on. A good mechanic can do a drain test on the battery to see what may be draining the charge. A dead cell in the battery itself will also cause the battery to go dead. Disconnect the negative battery cable overnight and if the battery is dead the next morning it has a dead cell and must be replaced. If not look for a light that is on or a relay that is stuck.
That light doesn't mean that your battery needs to be replaced. It means that your battery is not being charged while the car is running. Have your alternator tested.