6 Symptoms Of A Bad Ground Strap (Negative Battery Cable)

The ground strap may seem like a small part, but it is responsible for the entire electrical system in your car. Here's how to tell if you have a bad ground strap.

Symptoms Of A Bad Ground Strap

If you are having a lot of electrical problems with your car at the same time, the problem is very likely to be a bad ground strap.

The ground strap connects the negative terminal on the battery to the car’s body.

It is also called the negative battery cable. Almost all of the car’s electrical components flow through this cable. But what can happen when this ground strap starts going bad?

In this article, we look at the symptoms of a bad ground strap, its location, function, and the replacement cost if you need to replace it. Let’s begin with a quick overview of the signs to look for.

Symptoms Of A Bad Ground Strap

The most common symptoms of a bad ground strap are flickering headlights or problems starting the car. You may also experience issues like warning lights on the dashboard or other strange electrical issues.

While these are not all of the signs, a bad ground wire can cause a lot of strange symptoms in your car’s electrical system. Here is a more detailed list of the signs of a bad or failing ground strap to look for:

1. Flickering headlights

Dim Headlights Car

One of the electrical components that requires a lot of power is your car’s headlights. If the ground strap is bad, you will experience flickering lights. If this is not rectified, it can actually also damage your headlights.

If you have a newer car with LED headlights, there is no risk that they will flicker or dim down; instead, they will maybe shut off completely.

If you experience flickering or dimmed headlights, it is definitely time to check the ground strap.

2. Warning lights

Dashboard Warning Lights

If you have a modern car, your vehicle will be equipped with a lot of different control units. If your ground strap is going bad, you will get ground problems to these control units, which will therefore cause warning lights on your dashboards, like the check engine like, ABS warning light, or battery light, for example.

You might also have problems communicating with the control units if you attempt to troubleshoot them with your diagnostic scanner.

3. Battery not charging properly

Car Battery Charger

If your battery is not getting charged properly, but you are sure the alternator is functioning well, the problem could be with the ground strap.

If not enough electricity can flow through the ground strap, the alternator will not recharge the car battery.

There could also be other causes why your car battery is not getting charged, so you will need to rule out all these factors before concluding that it is the ground strap that is the problem.

4. Low voltage

Measure Car Battery Voltage

Another sign of a faulty ground strap is that you have low voltage circulating in your car. A simple voltage test will reveal whether you are receiving full power.

A well-functioning battery should give you a reading of around 12.3 volts on battery power. Anything less than this is an indication of the battery not being completely charged.

When the car runs, you should measure around 14 volts between the battery terminals to know if the charging system is functional.

5. Problems starting your car

Starting Car

As you can understand, getting the car engine to turn over requires a lot of power. Ground strap related problems occur most often in things that require a lot of power.

Because of this, when you have a bad ground strap, you are likely to feel that the engine’s starter is turning much slower than usual, or maybe even not at all.

6. Strange Electric Problems

Fuse Box Electrical

A bad ground strap can cause all types of strange electric problems in your car, as we discussed before. If you experience many different electronic problems, there is a big chance that there is something wrong with the ground strap.

Ground Strap Location

Car Battery Ground Cable

The Ground Strap is located between the negative car battery terminal and the body of the car. You do also have a ground strap between the engine and the body.

It is often located in a very visible location, so finding it should not be a problem if you know where the car battery is.

How to Diagnose the Ground Strap?

Testing a ground strap is very easy. All you have to do is crank your car a couple of times, then let your engine run. Touch the ground strap to see if it created any heat at the negative battery terminal or the bolt to the body. Be careful, though, because it can become extremely hot.

When there is a bad connection together with something that draws a lot of power, it will create heat and even melt things. This is exactly what happens if your ground strap is going bad.

Ground Strap Replacement Cost

The average ground strap replacement cost is between $20 and $80, depending on the car model and labor costs. A ground strap costs $10 to $50 and labor costs $10 to $30.

Luckily, ground straps are often very cheap and easy to replace. It is easy to replace yourself, but if you want someone else to do it, you can expect $10 to $30 for labor work.

Remember that you will lose all memory functions in your car when you replace the ground strap, like the radio code, so make sure you have it before you start the replacement.

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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