How do you know if you have a bad battery or a bad alternator if your car won’t crank all the way up

When cracking my car all lights come on inside the dash but my engine wouldn't come on after awhile I began trying to get a jump I did this about three times nothing would happen so I let my car sit and tried again but this time my lights wouldn't come on at all! I again tried getting a boost but my car wouldn't crank I than moved around the negative post and my car lights will come on than quickly turn off help please!?
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
The lights in your car will take a lot less power to operate than the starter to turn over the engine. You should take off the battery connections and clean them with baking soda and water, then reinstall and tighten them. If it was the connections then you may be able to start the car now if the battery is good. After the car is running then look at the gauges to see if all are normal.

If your car is still unable to start after doing this, contact a certified mechanic who can ensure that your battery is operating as it should.

How to Identify and Fix Common car Problems ?

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If your car starts but stalls when you`re underway, your battery is probably not being recharged due to a faulty alternator. A squealing sound coming from the engine that gets louder when drains like the heater or sound system are on may be your alternator bearings.
Can You Jumpstart a Car With a Bad Alternator? It`s possible that your car will start even if your alternator is bad, but it will probably stall once the battery runs out of enough power to keep things running the way they should.
The most common reasons a Chevrolet Impala won`t start are a dead battery, an alternator problem, or failed starter.
The Likely Culprit: Starter

If you`re unable to start your vehicle, check and see if the headlights and dash lights come on. If they shine bright and clear, that means that the battery and alternator are likely not the cause of the problem. If they were, there wouldn`t be enough power to run the lights.

Use a voltmeter to check your alternator; rev your engine to 2000 RPM, keep the engine running, and test the battery with the voltmeter. If your voltage goes from ~12.2 V to ~13-14.5 V, your alternator is doing well. If your V stays the same or decreases, that`s a bad sign.
If your alternator fails when you`re far from home, you can typically drive up to 200 miles on battery power alone. That`s assuming your battery is in good shape and fully charged. Of course, it`s best to get the alternator repaired or replaced as soon as you can.
We`ll help you get this sorted out ASAP! The root of the problem is likely a dead battery. The rapid clicking noise you`re hearing is likely the last of the battery`s charge. Notice if your car lights are dim when you try to turn the ignition—dim lights will be another indicator that the problem is in the battery.
Why won`t my car start but I have power? If you attempt to start up your car but the engine won`t turn over and the dashboard lights up, then you most likely have an issue with your battery. You could have a damaged or corroded battery terminal, which is stopping the engine from starting up when you fully turn the key.
If the car cranks when you turn the key, but the engine won`t start, it could be because fuel isn`t getting to the engine. One potential reason for this could be dirty fuel injectors. Over time, the fuel injector nozzles can become clogged with rust, corrosion or debris.
A corroded or defective alternator diode will faultily continue charging the circuit even when the car off. This, in turn, will drain your car battery and cause the car not to start.
A corroded or defective alternator diode will faultily continue charging the circuit even when the car off. This, in turn, will drain your car battery and cause the car not to start.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

How do you know if you have a bad battery or a bad alternator if your car won’t crank all the way up
ANSWER : The lights in your car will take a lot less power to operate than the starter to turn over the engine. You should take off the battery connections and clean them with baking soda and water, then reinstall and tighten them. If it was the connections then you may be able to start the car now if the battery is good. After the car is running then look at the gauges to see if all are normal.

If your car is still unable to start after doing this, contact a certified mechanic who can ensure that your battery is operating as it should.

Water was spilled in the trunk which soaked the car battery. Car won’t start now. Does water destroy a car battery?
ANSWER : Hi, thanks for writing in about the concern with the BMW 320i. If the battery was submerged in water then it’s completely possible for the battery to short out and die. Your friend will need to have the battery replaced. Also be sure to get all of the water out of the trunk. Have a certified technician, like one from YourMechanic, help you guys out if you need assistance with replacing the battery. Good luck.

Car won’t crank when it’s cold and now won’t start at all
ANSWER : Hi there:

Usually this issue is cased by low cranking amps inside the battery. If you’ve recently had the battery replaced, it’s possible that an electrical component that makes up the charging system might be damaged or faulty. It’s also quite possible that the main electrical relay or the starter relay is giving you fits. To know for certain what the exact issue might be on your 1989 Toyota Camry, you should have a professional mobile mechanic complete a car is hard to start inspection, so they can pinpoint the source of your issues and recommend the right repairs.

is the ecm the problem if battery light is on and the alternator isn’t bad
ANSWER : This is likely a sign of a failing voltage regulator. This is a unit that regulates the charging of the battery by the alternator. In your case, it sounds like the voltage output from the alternator may be much too high resulting in overcharging the battery and burning up wires in the process. I would recommend having an expert from YourMechanic come to your location to diagnose and properly test your vehicle’s charging system.

Car died while driving so I replaced the alternator and battery and car won’t attempt to turn over. What else could it be?
ANSWER : The initial failure was likely caused by a sudden fuel system (e.g., failed fuel pump) or electrical (including ignition) faiure. Prior to performing diagnostics be sure you have a fully charged battery that passes a load test. Then, confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the starter motor is not functioning, check for power to the starter motor when the key is held in the "start" position. If there a large voltage drop at the starter motor or no power at all, you may have a faulty ignition switch but you do have to check out the entire starter circuit, which includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch and terminations. On the other hand, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. If you desire that a certified mechanic resolve this, please simply request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Please let us know if you have further concerns or questions as we are always here to help you.

Car won’t start. The check engine light, battery light, and oil change light are coming on. I tried jumping the car and nothing happened. Why won’t my car start?
ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

2005 Chrysler 300C changed battery and alternator. Car started, ran, and then battery light came on. Shut car off and wouldn’t start.
ANSWER : Hi. There is a couple of things that could be wrong here. The battery or alternator that was just installed could be defective. Theses parts need to be tested for proper operation. There also could be a fuse, fusible link, or wiring for the battery or charging system that is blown or broken causing the battery light to come on.

The codes that you have will cause the car to shut down, run rough, or not start at all. The crankshaft sensor and camshaft sensor should be replaced. I suggest having a certified technician from YourMechanic come diagnose the charging system and check engine codes to help you proceed with correct repairs.

When changing the car battery, do you "register" the battery to the car computer?
ANSWER : Hi there. Changing the battery has nothing to do with programming a battery. If the car was flat dead with a battery that lost all of the power because the dome light was on, then when jumped the vehicle will run fine. What may need programmed when the battery is replaced is the key fob. The key fob will lose programming to the computer as the vehicle computer is reset. However, if a 9 volt battery saver was put into a cigarette lighter and the car battery was removed, then the computer will not lose its memory and be just fine. If you need further assistance with your battery, then seek out a professional, such as one from Your Mechanic, to help you.