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Where Is The Ground Strap On A BMW? [And How Do You Replace It]?

The BMW is a comfortable, high-performance luxury car that has a superb interior and provides a smooth ride. Like all other cars, your BMW has a vital component known as the ground strap. Do you know where it is located, its functions, and how to replace it? To help you with these questions, we consulted with experts who provided the answers below.

The location of the ground strap in your BMW depends on the year and model of your car. A failing ground strap can affect the performance of your car and will require replacement by following these easy steps:

  • Locate the ground strap
  • Gather materials and tools
  • Disconnect the battery
  • Remove the ground strap
  • Clean the connections
  • Fix the new ground strap
  • Re-connect the battery

Keep reading to learn where the ground strap is located on your BMW and how to replace it. In addition, we will help you understand why it is important and what happens when it is damaged. Included are the signs of a failing ground strap and the cost of replacing it. 

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Bmw 3 Series 330e door handle light projecting on the ground front end, grill, headlights and wheel details, Where Is The Ground Strap On A BMW? [And How Do You Replace It]?

How Do You Replace The Ground Strap Of Your BMW?

New BMW cars for sale

Generally, the ground strap is made from tinned copper wires braided together with metal connectors at each end. Your BMW has such a strap.

It connects the engine to the chassis or the negative terminal of the battery. In the event that there is a power surge or short circuit, the ground strap dissipates the extra electrical energy.

A corroded or damaged ground strap can cause several problems in your car. Some include your battery not charging, headlights flickering, or your car refusing to start. We shall look at these and more later in this post.

Replacing your ground strap is a solution to stopping these problems. It’s relatively easy to replace it, but, as always, if you are not up to the task, call a mechanic. 

Have a look at this ground strap on Amazon.

Below are steps to guide you:

Locate The Ground Strap

The position of the strap on a BMW depends on the year and model of the car. You can find out its location from your owner's manual or a professional. You can also look for it by checking underneath your car. In most cases, you will find it around the periphery of the engine adjacent to the vehicle’s frame. 

Gather Materials And Tools

Purchase your new ground strap and dielectric grease. The tools you will need are: 

  • Socket wrench
  • 13 mm socket and wrench
  • 10 mm socket wrench
  • Socket extensions
  • Shop towels

Disconnect The Battery

Park your car. Make sure you apply the emergency brake and block the wheels. This will ensure your safety since you’ll be working under the car.

Depending on your model, the battery is either in the trunk floor center or behind the trim panel on the right. To disconnect the battery, use a 10 mm wrench to unscrew the bolt and remove the negative connection.

Use a 10 mm wrench to unscrew the bolt and remove the connection. The video below explains how to do this:

Remove The Ground Strap

The strap is held in place by two 13 mm nuts on each end. To remove the nuts, use a 13 mm socket wrench. Using the extensions will make your work easier. 

This is an extension set that you can find on Amazon.

Clean The Connections

You may pour baking soda mixed with water on the connections. Scrub with a wire brush to remove the corrosion. Rinse the baking soda and dry the connection using a towel. If there’s too much rust, scrub with sandpaper until the metal shines. 

Fix The New Ground Strap

Take your new ground strap like the one shown above and screw back the nuts you had earlier removed to hold the strap firmly in place. Afterward, apply dielectric grease to protect the connections from rusting. That’s why you had to clean the connections to remove any rust.

You can find this dielectric grease on Amazon.

Wipe off excess grease using a shop towel like the one shown below. 

Have a look at this pack of shop towels on Amazon.

Re-connect The Battery

Screw back the bolts you removed and reconnect the battery.

Signs Of A Damaged Ground Strap

Early signs can help prevent problems arising from a bad strap. Some of the common symptoms include:

Flickering Lights

BMW 530d Car Head lights

A worn or damaged ground strap will interfere with the electrical circuit of your car. As a result, your headlights can be affected and start flickering. They may also regularly go dim. 

In some cases, the strap is just loose and needs to be tightened to secure it firmly. Otherwise, you should have it replaced. 

Low Voltage

When your car has low voltage, it will start up slowly, or as mentioned in the previous paragraph, the lights will go dim. You can test the voltage coming from your battery using a digital multimeter. 

Have a look at this multimeter on Amazon.

Connect the red point to the positive terminal of the battery, and connect the black point to the negative terminal. It should give you a reading of around 12.06 volts. 

Next, connect the black point to the ground strap, which should read 12.06 volts. If it is below this, the strap has a problem. Afterward, connect the black point to the surface of the engine, which should also read 12.06 volts. A different reading means the strap is faulty. 

Difficulty Starting Your Car

Motor problems

There are numerous reasons your car may not start. But, if you hear tapping sounds, your ground strap could be faulty. The tapping noise comes from the solenoid because it is not getting enough voltage. It opens and shuts quickly as it is not able to start up the engine. 

Weird Electrical Problems

You might think your car is haunted when it starts behaving abnormally. For example, you could switch on the air conditioner, but instead your windows roll down. This should not alarm you. That is what happens when the ground strap is not working. You could experience even stranger happenings in your car. 

Warning Light On Dashboard

Since a bad ground strap causes the battery not to charge properly, it will have low voltage. As a result, a battery warning light may appear on your dashboard. Damaged wiring or a faulty alternator could also cause this warning to appear. It could also cause the check engine light to show. 

However, if you recently replaced your strap, this message would mean something else is wrong. Any warning on your dashboard should be taken seriously.

Cost Of Replacing A Ground Strap

A Man is Paying Repairment of his Car with a Credit Card.

The average cost of a ground strap is between $10 and $50, though it depends on the model of your car. Labor costs to replace it can range between $10 and $30.

Replacing the strap is relatively easy. However, it is recommended that a mechanic replace it, especially if you do not have the skills. You might cause more damage, resulting in higher repair expenses.

If you do replace it yourself, you might lose the memory functions of your car. You should save the memory before replacing it the strap.

Reasons Ground Straps Fail

Ground straps are an important part of our cars and can fail mainly due to:

Corrosion

Ground straps can fail because of corrosion. This causes it to harden and lose its flexibility. It will not be able to conduct electricity. 

Cracks

The movement of the engine can cause the straps to wear over time. As a result, cracks form leading to slow cranking of the engine. The engine may eventually refuse to start. If you take a long time to address the issue, the strap can break.  

In Closing

The ground strap in your BMW is a very important component. It helps to disseminate any electrical surges that come about due to a short circuit.

A malfunctioning strap can cause your car to experience many problems. However, there are signs to show you early enough that your strap is not working properly. This can help avert these issues before they get worse. It's good to allow a mechanic to diagnose if the strap is the actual problem.

Replacing a strap is easy and inexpensive. You could replace it by yourself, but remember—it’s better to hire a mechanic who has experience with this kind of job.

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