You may have a short circuit somewhere that is leaking current to ground. Or you could have a bulb or accessory that is using current even when the vehicle is turned off. Improperly installed aftermarket stereos & amps are a notorious cause of this.
Then either something is on draining the battery or the battery has a dead cell draining all the rest and must be replaced.
Your alternator is shot.
this just happened to us -- after installing new starter, it turned out that the battery connection was not correct -- auto parts store checked and cleaned terminals and fixed connection, all for free. this just happened to us -- after installing new starter, it turned out that the battery connection was not correct -- auto parts store checked and cleaned terminals and fixed connection, all for free.
If you are 100% sure that the battery is good and all the connections are clean and tight, then you need a new starter. But make sure all that is okay first. does it have the right starter on it to start with? Have you been working on the engine and have it out of time??
If the starter motor is spinning but not engaging it won't help to hit it with a hammer. The "starter drive" portion of the starter is shot. If all you get is a click or no noise at all, you might get lucky by hitting it, assuming the battery and all connections are good. This technique may work once or twice if the starter is at fault. The starter is located under the vehicle. You can follow the path of the positive battery cable from the battery to locate the starter. The positive battery cable will pass thru the starter solenoid on the inner fender then continue down to the starter.
If the starter is "clicking" then check the battery to make sure that is has enough juice to turn the starter. If the battery is good. It could be your starter solenoid is bad. Most of these are built into the starter nowadays. You will have to have the starter changed. I am betting on the battery especially if it is older. Another culprit could be your alternator failing to charge your battery.
sell it
A starter does drain a battery. The battery holds a charge so that you can use your starter to start the car. After the car is started the alternator recharges your battery and runs your car and all it's accessories. If your car won't start or is having a hard time starting you can drain your battery by repeated unsuccessful attempts to start it.
You have a voltage drop in either the positive or negative battery cable. Clean all of your cable end connections ( at the starter, the engine block and again at the battery terminals). You have a voltage drop in either the positive or negative battery cable. Clean all of your cable end connections ( at the starter, the engine block and again at the battery terminals).
if you have good battery and cable connections, the starter motor or starter relay is bad
most times ther is a short in the circut. maeanig that a wire in the circut that is supposed to be hot at all times, even with engine off, is connecting to ground(body or frame of car) and battery is constantly draining.
first disconnect the battery. remove the bolts that support the starter. you may have to wiggle the starter out after you disconnect all of the wires going to the starter