Here's why:
* The Alternator's Job: The alternator recharges the battery while the engine is running. It's the power source for all electrical components *while the engine is running*.
* Stalling Engine: When the alternator fails, the battery is no longer being recharged. The car relies on the battery to initially start and power some systems. Once the battery's charge is depleted by powering the car and accessories, the engine will stall because it lacks the power to keep running.
* Battery Light: The battery light is directly connected to the alternator's charging system. When the alternator isn't charging, this light will come on as a warning.
Other (less likely) possibilities:
While alternator failure is the most probable cause, other issues *could* contribute to a similar symptom. These are less likely but worth considering:
* Bad Battery: A very weak or failing battery *could* also cause a stall, especially under load (like using the AC or headlights). However, the battery light would likely be on *before* the stall in this scenario, unless the battery completely fails instantly.
* Loose Battery Cable: A loose or corroded battery cable connection can interrupt the charging circuit and cause similar problems. Check these connections for tightness and corrosion.
* Other Electrical Issues: A rare electrical fault elsewhere in the car could draw excessive current, depleting the battery and causing a stall. This is less common.
What to do:
1. Safety First: Pull over safely and turn on your hazard lights if your car stalls.
2. Check Battery Terminals: Inspect the battery terminals for corrosion or looseness. Clean them if necessary.
3. Jump Start (Caution): If you can safely jump-start the car, this may rule out a completely dead battery but won't fix an alternator problem. Drive it to a mechanic immediately if you succeed in jump-starting it.
4. Call a Mechanic or Tow Truck: The most likely solution is that your alternator needs to be replaced or repaired. Don't try to drive the car long distances with a faulty alternator.
In short, the combination of a stalled engine and a lit battery light points very strongly towards a failing alternator in your 2002 Oldsmobile Alero. Have it checked by a mechanic as soon as possible.
