Do You Have To Disconnect Battery To Change Ignition Coil?

The ignition coils in the engine of your car are essential. It’s the component that produces the electricity that’s ferried to the spark plug (through the ignition cable). Like any other component in a car, the ignition coil is prone to breaking. A broken ignition coil is what results in a misfire or even an engine failure.

It’s at this point that many people are always asking if they have to disconnect the battery to change the ignition coil. Yes, unplugging the battery is much recommended as it ensures that you don’t get shocked or short the electrical system while working on the replacement.

A Guide on How to Replace an Ignition Coil

As said earlier, the ignition coil in your car is no exception. It’s also prone to breaking. There are many ways to tell if the coil is faulty or not.

For example, if your car develops a problem with starting. The coil may be one of the components causing the trouble. The best way to eliminate the problem is by shopping for the right replacement. You don’t need a specialist to get the job done. With the guide I will provide below, you can handle the work more like a professional.

1. Confirm that the Ignition Coil Has a Problem

One symptom of a faulty ignition coil is experiencing problems when starting the car. But, whenever you encounter this trouble, it doesn’t mean that the coil is the only cause. Your vehicle may be failing to start because of a faulty battery or something else. Therefore, you have got to confirm that the coil has an issue before proceeding to the next step.

The fastest way to perform the test is by connecting an electronic tester to the ignition module. You can find it in the engine housing nears the distributor. If you test a low energy reading, it means that the ignition coil isn’t transmitting sufficient energy to the spark plugs. Therefore, starting your car may prove difficult.

2. Prepare for Extraction

Once you confirm that the coil is faulty, your next move should be to prepare the way for the removal. You need to begin by unplugging the vehicle’s battery. As said earlier, disconnecting the cell ensures that both you and the electrical components are safe from electrical short. After the battery is out of the picture, you should open the screws holding down the electrical wiring to the ignition module.

Remember, to keep the screws somewhere safe as you will need them later. Next, proceed to open the coil’s casing to reveal the part itself. The ignition coil looks like a large cylinder with a cap and two electrical lead at the top. That shouldn’t be hard to find.

3. Inspect the Old Ignition Coil

After removing the coil, you should start by performing a physical examination. You should look for things such as cracks, bents, and broken or even missing wire connections. These are some of the conditions that may have caused the ignition coil to fail.

4. Inspect the Ignition Module As Well

The inspection doesn’t end with checking the ignition coil alone. You will need to go ahead and observe the faults at the ignition module also. Check both the interior and the exterior of the module. You should look for clues such as missing, bent, broken, cracked, or twisted electrical connections and damages to the housing or porcelain insulation.

If you notice any damaged wires, go ahead and fix new wires before inserting the new coil. At times the damage may appear to be much, and that means that you may have to replace the entire module.

5. Insert the New Coil

By now, you should have a new ignition coil, and that matches your car. Remember, every car comes with a unique coil. Therefore, you should specify your car model to your auto dealer when shopping for a replacement. The trick saves you from the last-minute surprises. If you have the right coil, you should proceed and insert it in the module as the old one was placed.

Attach the wires to the leads and enter the ignition module to its initial location. Go ahead and secure the module using the screws that you had obtained. Confirm that all the wires are connected correctly, and not even one of them is protruding from the ignition module housing.

6. Reconnect the Battery to the Module

Next, go ahead and reattach the battery cables you had disconnected earlier. This should allow electrical power to flow to the ignition module.

7. Test the New Ignition Coil

Now that you have installed the new ignition coil, your next move should be to test and confirm that the cable is functioning efficiently. You should go inside the car and turn on the ignition. If the coil was the problem, your car should now start quickly and effectively. If that’s the case, then you just replaced the ignition coil successfully.

How Long Should an Ignition Coil Serve You After a Replacement?

The ignition coil in your car is a component like any other. By saying this, I mean that it has a lifespan, and that means that you will need a replacement on one occasion or another. Most coils in the market today are designed to take your car for 100000 miles.

But, as per the US Federal law, an ignition coil and module are warranted to serve your vehicle for two years. In other words, the coil should take the car for at least 24000 miles, whichever comes first. However, you should know that the insulation of the coils will degrade over time.


The cases of waking up to a dead ignition coil are not new. The fact that the ignition coil is a vital component calls for an instant replacement to allow your car to start quickly and easily.

It’s at this point that most people are always asking if it’s a must to disconnect the battery when replacing the coil. It’s recommended that you disconnect the battery from the ignition module for safety reasons. Explained in this article is a step-by-step guide you ought to follow to handle the replacement like a pro.