You may know enough about your vehicle's propulsion system to know that if it won't start in the morning and there seems to be no power, it's likely to be either the alternator or the battery. If you are turning the key in your ignition and the car simply won't start, how can you narrow down the cause of the problem?
Firstly, when was the last time that you installed a new battery? If it's been a number of years, then it may just have reached the end of its tether. If you're somebody who may not be as attentive when it comes to general maintenance, the battery could give up the ghost a little earlier.
Maybe It's the Battery?
To determine if the battery is the culprit, have a look at the gauge on the dashboard without turning the ignition. Is it showing any charge at all? What happens when you turn the windshield wipers on? If they barely move, the charge might be very low.
To narrow it down even further, get somebody to help you start the vehicle by connecting their car to yours with jump cables. Let it run for a while, and then switch everything off again. Now, try to restart on your own, and if you are unable to do so, this indicates that the alternator is working properly. After all, it's helping the battery to keep the engine running, but the storage unit is not capable of retaining the charge and starting the engine by itself.
Could It Be the Alternator?
If, however, you find that the battery is working, then you have to consider the alternator. When the engine is running, have a look at the lights on the dashboard and see how clear they are. If they are getting gradually dimmer, the alternator is faulty. You can also check for problems by looking at the efficiency of the headlights. If you notice that they become dimmer when the car is at a standstill, then the alternator is not functioning as it should.
Sometimes, the alternator will make a noise akin to a growling sound when it is on its way out. It may also start to smell as if it were burning, due to it overheating internally.
Now that you've been able to narrow everything down, you can either take your vehicle in to get the alternator checked or swapped out, or buy a new battery. Contact an alternator repair service for more information.