Testing the alternator in your 1.6L Honda Civic, to see if it is bad (or not), can be accurately done with just a multimeter.
Not only that, testing it is easy and fast and in this tutorial, I'll show you how.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar El Alternador (1996-2000 1.6L Honda Civic) (at: autotecnico-online.com).
Symptoms Of A Bad Alternator
Since the alternator provides the electrical current that your Civic needs once it starts and charges the battery so that it's ready to crank the car the next time so when it fails, you'll notice one or several of the following symptoms:
- The charge light (also known as the battery light) will be shining nice and bright on your Civic's instrument cluster.
- Whenever you turn on the headlights (night driving), they glow very dim.
- The car won't crank. It will only crank and start if you jump start your Civic.
- The only way the car cranks and starts is if you charge the battery.
TEST 1: Battery Voltage Test With Engine Running
This very first test will confirm that the alternator is either not working and thus not charging the battery or it is working and thus charging the battery.
We'll do this by simply checking the battery's voltage with your Civic's engine running and your multimeter set to Volts DC mode.
NOTE: For this test to be effective, the battery has to have enough of a charge to keep your Civic running for at least 5 to 10 minutes. So, if the battery is completely dead, charge it up.
These are the test steps:
Crank and start your Honda Civic and select Volts DC mode on your multimeter.
Probe the positive battery terminal with the red multimeter test lead.
With the black multimeter test lead, probe the negative battery terminal on your Honda Civic's battery.
Your multimeter is gonna' register one of two possible readings and they are:
1.) A steady 13.5 to 14.5 Volts DC.
2.) Or 12.5 Volts that will decrease the longer the engine stays running.
Put an electrical load on the alternator to further confirm that it's either charging or not charging.
This can be very easily done by turning on every accessory possible (inside the vehicle). Turn on the A/C or heater on high, turn on the windshield wipers, turn on the headlights, turn on everything and anything that uses electricity inside and outside of the vehicle.
Your multimeter will show you one of two things (as you turn on all of this stuff):
1.) The multimeter will register a nice and steady 13.5 to 14.5 Volts DC no matter what gets turned on.
2.) It will register 12.5 V DC and this voltage will decrease more and more as you turn on stuff inside your Honda vehicle.
OK, let's interpret your multimeter test results:
CASE 1: Your multimeter registered 13.5 to 14.5 Volts. This is good and it tells you that the alternator is working and is charging the battery and providing enough juice for the electrical needs of your Honda Civic.
No further testing is required, since this multimeter test result eliminates the alternator on your Honda Civic as bad.
CASE 2: Your multimeter registered a voltage that steadily dropped down to 9 Volts. This is a clear indication that your Honda Civic's alternator IS NOT charging the battery.
Replacing the alternator at this point usually solves around 90% of the No Charge conditions on any 1.6L Honda Civic around the world. That's right, you could stop testing here and say: ‘The alternator is fried’ and be done but..
I suggest two more easy tests to be absolutely sure it is bad. For the first test of the two, go to: TEST 2: Checking The Continuity Of The Bat (+) Cable.