A vehicle's alternator is an important aspect of the mechanical system. The alternator is responsible for charging the battery when the vehicle is being driven. This ensures that when the engine is turned off the battery will be fully charged and will be able to restart the vehicle when it is turned back on. A bad alternator can cause a litany of problems, from a dead battery to poor illumination from the interior lights and headlights. A bad alternator can also leave you stranded if it fails.
The alternator is responsible for keeping the vehicle's battery charged. If the engine turns over slowly and is difficult to start, particularly when cold, the problem may be that the alternator is beginning to fail and is not properly charging the vehicle's charging system.
Just about every vehicle, particularly modern ones, will have some type of warning light on the dash somewhere that will start to glow if the alternator is not functioning correctly. These warning lights will often say "ALT" or something similar. If the alternator warning light does not turn off a few seconds after the engine has been started, the alternator may be failing.
If the charging system (the battery) in your vehicle is not being properly charged by the alternator, another symptom may be dim headlights and interior lights. If you notice that your lights are not as bright as they normally are, then the alternator may be on the way out.
If your battery continually dies after the car has been sitting, it may be because the alternator is not doing its job of charging the battery properly. If you drive at a high rate of speed on the freeway for an extended period of time and the battery dies, then the alternator may not be functioning. Keep in mind that a low or dead battery is not only caused by a bad alternator. The battery maysimply be old and in need of replacement. There also may an electrical drain on the system that is killing the battery.
