How to Test a Ford Coil Pack with a Multimeter

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A ford coil pack is a collection of ignition coils that play the crucial role of starting your car, and are often designed to perform heavy duties. However, they still are prone to get damaged easily whenever there is vibration, poor installation, as well as excessive heat. Any time your ford coil pack starts to fail, you then are most likely seeing the start of your car developing several issues. 

Therefore, if you suspect that the ford coil pack is defective, you then need to go ahead and have it tested with a multimeter and hence know whether or not it needs to be replaced. Thanks to this performed test, you will be in a better position to make an informed decision about the repair or replacement needed to be done to restore your car to a functional state.

So, how do you tell when your ford coil is faulty? Here are some of the main signs you need to keep an eye out for; 

  • Any sign of a bad ford coil pack
  • Excessive consumption of fuel
  • Low vehicle power
  • Engine failing to work appropriately
  • Experiencing challenges whenever you want to start your car
  • A loud and noisy engine

Perform a test on your spark plug

This is one of the best ways to test whether your ford coil has any issue. However, you need to exercise enough precautions when performing this test on your spark plug, so you should always open the hood and make sure to switch off the engine of your car. 

Subsequently, find the spark plugs, and if you have no idea where they are found, you should refer to your manual script. Moreover, the spark plug switch can guide you to remove the plugs and thereby enable you to easily access your ford coil pack. During this entire process, confirm that the wires are correctly labeled to give you an easy time during the reinstallation.

Using an insulated plier, reattach the spark plugs as you hold it in position and then use a spark tester to fit the spark plug before you start your car’s engine. When the engine is on, observe whether your spark is moving from the electrode center to your spark tester’s metal area. 

Subsequently, examine whether a spark shows at the spark plug’s end and in case it shows, this is proof that your ford coil pack is working correctly, and you do not need to do any replacement. Nevertheless, if there is no spark at the end of your spark plug, this then means your ford coil pack has a problem and needs to be fixed or replaced.

Resistance test

This particular test is usually done using a multimeter and a wrench set. To conduct it, you need first to locate the ford coil pack in your car and then take it off from the engine of your car using a wrench. Consequently, remove the large wires from the center of your ford coil, and then take the wire nuts that are retained and attach them to the side terminals of the detached ford coil pack.

After that, set your multimeter on 200 ohms range, then switch it on and using the multimeter leads, attach the wires of your spark plug terminal to every coil. It would be best if you placed the multimeter leads on the side terminals on both sides, and it does not matter which particular lead is placed on the negative or positive terminal since it does not affect the results that will be displayed. This particular test is for examining primary resistance. Take a look at the reading displayed, and ideally, it needs to range between 0.4 to 2 ohms.

Once this is done, test the lead that has been moved from the negative terminal to the center where you currently removed the larger wires as you maintain the other lead on the positive terminal, with this, meant to examine secondary resistance. The reading value displayed should range from 6,000 to 10,000 ohms, and for more details, you can always refer to your user manual.

In case you realize that your coil is defective, that is, if the readings displayed are not within the ranges mentioned above, make sure you get it replaced immediately. However, if the readings are within the reading value discussed earlier, place back the wires and tighten the nuts. Confirm you fix everything back in the same position as before since replacement is not necessary, and to do this, you can use a wrench to tighten the nuts.\

Additionally, reinstall your larger coil wires on the terminal center of the coil in the same manner. You should put in place some energy to push it in position, ensure it is well fixed to avoid it coming out loose while the engine is still running.

Switch signal test

Examine whether your ford coil pack is getting 12 volts when your engine is on, you can only examine this through the use of a multimeter. Furthermore, you should verify that it gets its signal from your control module through the use of LED light, and after that, remove your ford coil pack from the connector.

Consequently, carefully insert the red lead back to the power circuit connector and on the other terminal, place the black lead. After this, have someone turn on the engine of your car and observe if both circuits your LED flashes. If it does, this is a clear sign that your ford coil pack is faulty and needs to be replaced.

Some of the precautions you need to have in mind during this test are; 

  • Make sure you use a spark tester to examine your spark.
  • Use the mentioned device strictly when running your tests.
  • Do not dare to remove the spark plug wire from your ford coil pack.
  • Use gloves while running your test on the ford coil pack.


Having read through this article, you now know of the exact steps to follow when testing a ford coil pack with a multimeter. Therefore, whenever you suspect your vehicle is experiencing any such problem, you should not rush to get a mechanic, but instead, confirm for yourself if the ford coil pack is working properly.

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