I'm not sure if your alternator is in tip top shape.If you don't know what to look for, it's hard to tell if an alternator works or not.The easiest way to test it is by using a voltmeter.There are a few other methods you can try if you're well-versed in your car.The test is to check the health of your battery.There are newer vehicles with computer controlled charging systems that need additional testing.
Step 1: You can buy avoltmeter.
At any auto parts store, you can find one for less than $20.You don't have to worry about getting an expensive one; a cheap one will suffice.You can use a multimeter if you have one.A multimeter is used to measure electrical properties.When you're checking your alternator, you want to measure the voltage.
Step 2: The battery should be checked first.
In order to start the vehicle, the battery needs to be charged, and the alternator must be spun at enough speed to keep it charged.If your battery is too low, you won't be able to start the vehicle and you'll also be unable to test the alternator, which is useless.Your battery could be the problem if the weather is cold or it is old.Before checking the alternator, you need to check the battery.Turn off the car.It's important to make sure your engine is off.Open the hood.The battery needs to be connected to thevoltmeter.The positive battery terminal has a red lead and a black lead.Don't touch your skin to the battery.It is a good idea to read thevoltmeter.The battery can be tested with the voltmeter if it reads above 12.2 volts.Try a different method for checking the alternator if the battery doesn't have enough voltage.
Step 3: The engine needs to be revved to 2,000 RPM to start the vehicle.
This will cause your voltage regulator to kick the alternator into high gear, since it will draw power on your battery.
Step 4: Try to keep the engine running and retest the batteries.
The voltage should go up to at least 13 when you read the voltmeter this time.Your alternator is in good shape if the voltage fluctuates between 13 and 14.5 volts and if it stays the same or decreases.The process should be repeated with the lights, radio, and AC on.If the battery voltage stays above 13 volts with the engine at 2,000rpm and all accessories on, the alternator is charging.
Step 5: The gauge on the alternator needs to be checked.
The gauge will read the output of the alternator for you.Turn on the blower fan for the AC or Heater, and watch the gauge to see if it decreases the voltage or amperage, if you want to run the engine at 2,000rpm for tests.If the voltmeter is higher when the engine is running than when it is not, you can assume that the alternator is charging.
Step 6: Listen to the engine running.
If there is a problem with the bearings, you may hear a sound coming from the front of the car, which becomes louder with more electrical accessories using power at the same time.
Step 7: Make sure the radio is turned on and the engine is running.
There is no music on the AM band.The radio is most likely the culprit if it whines or goes fuzzy when you hit the gas.
Step 8: You can find an auto-parts store that tests your alternator for free.
Since every store would love for you to buy your new alternator from them, many will try to get the edge-up on their competitors by offering free testing.Bring your alternator in to be sure.