How To Test a Honda Accord Alternator

How To Test a Honda Accord Alternator

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There’s quite a few things that can go wrong when it comes to your alternator, from battery failure to sluggish performance. This is why it’s a good idea to learn how to test a Honda Accord alternator. Problems with your battery voltage can lead to misdiagnosed trouble codes, or your car even failing to start or run.

Performing these tests to see if your Honda alternator is working is very easy to do, and only requires a few hand tools. One tool you will need is a multimeter, if you are not familiar with how to operate a multimeter, check out our handy How To here.

Our DIY article on how to test a Honda Accord alternator is broken up into three different tests. Checking the operation of your alternator with the engine running, checking the battery cable and checking your alternator fuse box. Our last section details how to remove the Honda Accord alternator as well as servicing it.

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The alternator or automotive generator in your Honda Accord is located to the right in the engine bay. This unit is secured by one 12mm bolt as well as a tensioning bolt. The part number for this unit is 31100-PAA-A01, 31100-PAA-A01 or 31100-PAA-L71, and by the time you’re done reading our guide, you’ll know how to test a Honda Accord alternator as well as remove one.

How To Test a Honda Accord Alternator – Testing your Alternator in the car


 

Before you begin our DIY How To guide, make sure that you are taking the proper precautions when testing your Honda Accord alternator in the car. Because there are moving belts as well as the danger of your operating fans, make sure to keep all hands and clothing free from danger. For a guide on how to stay safe while working on your car, check our Safety Guidelines here for a few pointers.

To begin our first test in our DIY How To Test your Honda Alternator, start your Honda Accord with the hood open. If your battery is dead, make sure to charge your battery fully before starting your Honda Accord.

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With your 2.2 liter or 2.3 liter Accord started, locate your battery on the left side of your Accord engine bay. Measure the battery voltage with your car started using the multimeter by placing the RED positive multimeter lead to the positive terminal, and the BLACK negative post to the other terminal.

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The multimeter should be reading one of two possible readings from your Accord’s battery.

  1. Steady voltage from 13.5 volts to 14.5 volts – Voltage does not fall or waver on battery terminal – This is the condition you want at your battery while your Honda Accord is running.
  2. Voltage that falls and continues to fall from 13 volts or lower – This is a condition that indicates an issue with your Accord’s charging system or alternator.

How To Test a Honda Accord Alternator – Putting Load on the alternator


 

In order for this part of our how to test a Honda Accord alternator to work, you will need to put some load on your alternator. This means you should turn on every single accessory and item in your vehicle that uses battery voltage. Turn on your air conditioning, headlights, wipers and anything else you could possibly think of.

Keep the multimeter connected and monitor the battery load as you begin to turn things on. Based on the alternator in your Honda Accord, and it’s condition, this part of our test should result in one of two things.

  1. Steady voltage that doesn’t waver when you turn on things in your Honda Accord.
  2. 12.5 volts that continues to fall or fluctuate when you turn on accessories or turn them off.

If your battery voltage dips and falls to 9 volts, chances are that your alternator or generator simply isn’t doing the job anymore. You will need to replace your Honda Accord alternator, with the part numbers provided above. Before doing that however, just one last step remains in our how to test a Honda Accord alternator DIY guide.

How To Test a Honda Accord Alternator – Testing Alternator wire


The last part of our how to test a Honda Accord alternator article goes over testing the continuity between the alternator and your battery. If your battery’s voltage is falling and continues to fall, there may be a break or fuse blown that’s preventing the alternator from charging your battery.

You will need to verify that your main fuse in your Honda Accord is working correctly. This is a 80 or 100 amp fuse located in the engine bay fusebox. Remove the negative terminal on your battery before testing your fuse. Remove the fusebox cover and inspect your main battery fuse for any signs of damage or overload.

Next you will be testing the battery terminal on your alternator with your multimeter. Turn your multimeter to OHMS mode, and check to make sure there’s continuity between the terminals. Put the red wire of your multimeter to the nut on your alternator and the black lead to the battery terminal.

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You should see a reading of .5 Ω or less, meaning that the inline fusible link is not blown. If your multimeter spits out an error, or shows there’s an over limit condition, you will need to replace the blown fuse. Because this inline fuse is meant to protect the battery and vehicle, if blown it will prevent the alternator from charging the battery.

Replace the 80 amp or 100 amp fuse inside your Accord fuse box and then start our tests from step 1 again. While you are there, make sure to check the 7.5 amp blade style fuse in the engine bay, this is for your alternator and if blown must be replaced.

How To Test a Honda Accord Alternator – Replacing your alternator


Replacing the alternator in your Honda Accord is very simple and easy to do. Loosen the 12mm nut that holds the side of your alternator bracket in place. Using a 10mm socket, back out the tensioner bolt that runs through the bottom of your alternator assembly. This will loosen the drive belts and allow you to slip off the alternator belt.

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Undo the 10mm nut that holds the battery cable in place on your alternator. Unplug your alternator and set the wiring harness to the side. You may or may not need to disconnect your air conditioning compressor connector to gain the proper access and clearance.

After backing out the tensioner bolt to your alternator and removing the alternator belt, remove the 10mm tensioner bolt all together. You should have a free moving alternator now, with your alternator bracket looking like the image above.

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Undo the remove the 12mm bolt and nut that runs through the top pivot of your Honda Accord alternator, and you’re ready to replace it. Install the top pivot bolt first when installing your replacement Honda Accord alternator, and make sure to setup your tensioner before installing or placing your new alternator in place.

Tighten your replacement bolts and put the proper tension in the bottom drive belt adjuster. When your new alternator is in place and proper belt tension has been set, start up your Honda Accord and perform the tests in our how to test a Honda Accord alternator to make sure you’ve got the job done!

Have any questions about our how to test a Honda Accord alternator DIY article? Leave them for us below!

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