• Once an alternator fails, the car will not run until it is replaced or rebuilt.automobile engine image by palms from Fotolia.com
  
  An alternator in a vehicle is responsible for keeping the battery charged. Because the battery powers the spark plugs and most of the electrical systems of the vehicle, a failed alternator causes various problems. Fortunately, before an alternator fails, there is usually some sort of sign, whether it be a sound, a light or just an overall difference in the way your car is acting. Fixing your alternator is necessary to avoid ending up stranded if it fails.
  
  

Car Misfires

• When a car misfires, it feels as though it is jerking when you're up to speed. Because there are many different culprits for this, it is best to examine the rest of the car before jumping to conclusions. However, if your vehicle is experiencing other failed alternator symptoms, it is best to get it replaced. Once an alternator fails, the car will cease to run. Alternators provide the electrical power and voltage to the vehicle.
  
  

Stalling Out Under Power

• Stalling out or losing power might leave you stranded and frustrated.girl, broken down image by NatJag from Fotolia.com
  
  If when you hit the gas or turn on the radio or air conditioning, your car starts to misfire or stall, your alternator could be to blame. Sometimes even starting the vehicle might cause it to lose power. If it turns over fine but acts up when you hit the gas or use any kind of power in the vehicle, it might be time to look into a new alternator.
  
  

Dim Lights

• Your dash might attempt to warn you of problems with the alternator.tbird dash image by Michelle Marsan from Fotolia.com
  
  After starting your car, you might notice your dashboard lights or interior lights appear a little dim. Although this could signal a short in the wire (especially if cutting in and out), it might also be the alternator. The alternator is responsible for powering the lights inside your vehicle, so they might dim or the alternator light might come on indicating something is amiss.
  
  

Strange Sounds

• As you're driving, listen for any different sounds such as metal-on-metal grinding or clanking. This sound might indicate the shaft on the alternator is giving way. If it breaks, your car will refuse to run. In some situations, it might sound like a rattle as the car is running. Have the alternator checked if you hear any of these sounds, as they might be signs the alternator is ready to stop working.
  
  

Dead Battery

• When the alternator starts to go bad, you might find your battery keeps dying as well. Because the alternator is what charges the battery, it might be to blame. After driving your vehicle and using battery power, the alternator recharges it. So, if you drove all day, turned off your car and it won't start the next time, get the alternator checked out, especially if your car is displaying other symptoms of a bad alternator.