Even if you’re like the majority of people and haven’t heard of the ground strap, it serves a very important function. If you are starting to notice some of the symptoms of a bad ground strap, you may be more interested in finding out about this necessary piece.
We’ve put together the top symptoms of a bad ground strap, as well as some potential tips on how to diagnose the symptoms.
We’re going to show you where the ground strap can be found, discuss the functionality of it, as well as its replacement cost, and then answer some of your burning questions.
Symptoms Of A Bad Ground Strap
If the ground strap is bad, headlight and dash warning lights will flicker. It may also prevent the battery from charging, the battery voltage may be low, or the car may start hard or not at all. There may also be some weird electrical system failures which don’t seem to make sense.
While some of these symptoms can be affiliated with a completely different problem, let’s take a closer look.
#1. Flickering Headlights.
As with any observing any charging system failure, you will have flickering headlights. When the ground strap is broken or not connected at all, the electrical circuit will encounter more than one major problem when delivering power to the headlights. This causes them to “flicker” or dim as time goes by.
If you notice flickering only one time, there’s a possibility the ground strap just came loose; you may have seen it rest in good position. However, it is more likely you are going to see the same problem develop and you are going to need to tighten or replace the ground strap.
#2. Dashboard Warning Lights.
With many different dashboard warning lights, it can be difficult to understand what the vehicle is telling you. In this case, the battery warning light is on the dashboard, indicating that the battery is low and not charging properly.
However, a bad ground strap is not the only source of this problem. The problem could also be due to poor wiring or a bad alternator. If, when the light is on, you need to get the car down the road just a little farther, you can help save the battery by turning off all electrical equipment (radio, air conditioner, etc.).
#3. Battery Not Charging Properly.
As previously stated, a bad ground strap can prevent the battery from charging. The vehicle must have a good ground to charge the battery.
Again, a dead car battery not just due to the ground strap. The battery could legitimately need to be replaced, or unfortunately, you could have a failing alternator. This is why it is important to fully diagnose before changing anything.
#4. Low Battery Voltage.
If your vehicle’s electrical system doesn’t seem to have as much power as normal, the ground strap could be a problem. A digital multimeter can help determine the voltage coming out of the battery terminals.
This reading should be approximately 12.6 volts when the car is not running. If it is lower than this, you have either some battery issues or a problem with the grounding.
#5. Problems Starting Your Car.
There are many reasons your car won’t start, but never rule out a bad ground. If the ground is bad, you will hear tapping noises when starting the car.
The noise comes from the starter solenoid opening and closing repeatedly. If the starter does not have a proper ground, it will not get the right voltage, but this will also happen with a dead battery.
#6. Various Strange Electric Problems.
If there is a bad ground you will notice issues in an electrical system, particularly when it is under a heavy load (such as when both your air conditioning is running and your aftermarket stereo with a subwoofer system is on, you will likely see strange things happen).
For example, if you try to operate two functions at the same time (power windows and high beams) you will likely notice that one of those functions doesn’t have the power it needs. Any extraordinary electrical problems should be investigated as a potential bad ground as well.
What’s The Function Of A Ground Strap?
The ground cable of the vehicle connects the negative battery terminal to the chassis. The ground strap completes the grounding connection from the engine to the body of the vehicle. Having the engine connected to these areas provides an alternative path for electricity.
For safety reasons, most electrical components must be grounded. Grounding the connection completes a circuit where electricity can travel through a designated path.
The electricity flows freely from the positive battery terminal to the electrical components needing the electricity, then through the ground connection.
In the event of a short circuit or power surge, the ground connection protects against damage because the energy can disperse in the ground connection. Electrical devices that rely on a ground connection include:
- AC compressor
- Radiator fans
- Stereo system
- Ignition system
- Alternator
You can find the ground connections of your car in the schematic on the service manual.
Where is the ground strap?
The ground cable runs from the negative battery terminal to the chassis and resembles a battery cable. The cable can sometimes become corroded and not fully function, since it is likely to corrode.
The ground strap connects the engine and the chassis and even though it is called a strap, it looks more like steel braided together to create a band.
The strap can fray and become damaged; it is subject to the elements, vibration, and heat or hot oil leaking from the engine. If enough braiding of the strap gets damaged, it can break and limit the ground strap from functioning optimally.
How Do You Test A Ground Strap?
To begin, you will want to visually inspect the ground strap first. Look for the plain black cable. This cable will be running from the negative terminal of the battery and connected to the car chassis (body).
Visually inspect the entire cable for damage. Even a small amount of damage, such as a nick or broken strands, can cause electrical interference.
Your car has multiple grounds, including a ground strap to the engine block. Be sure to locate all of the ground straps and visually inspect for damage as well.
If you do not see any physical damage, you may test continuity of the ground with a multimeter. A digital multimeter does not cost much money and is always handy for diagnostics like this.
- Park your car in a dry area. It must be completely dry.
- Remove any jewelry as you will be dealing with electricity.
- Set your multimeter to 20 V DC.
- Touch the red probe to the (red) positive battery terminal and the black probe to the (black) negative battery terminal. This reading should be approximately 12.6 volts.
- With the black probe, place it on the ground connection. This should also be 12.6 volts as well. If it is far below this, you have a faulty ground strap.
- With your black probe, now put it directly to a part of the engine block that is metal. This will be testing the ground connection to the engine. It should read in the specs in your service manual. If not, you will need to replace or reconnect the cable.
If your tests show nothing, you may wish to check for a blown fuse, especially if the car is not starting. If your symptoms are flickering headlights and some sporadic electrical problems, or trouble charging the battery with a new one, you may have a dying alternator as well.
How Much Does It Cost To Replace A Ground Strap?
Replacing a ground cable is inexpensive. It will cost you between $150 to $250 for a professional to replace it. The part alone will cost you about $20 to $40 with labor costing you about $130 to $210.
On some vehicles it can be complicated to access the ground cable which will make the duration of the installation longer. But, if you have the tools, you can probably figure it out on your own by getting a quality service manual. Service manuals give you diagrams and step by step procedures to fix things.
If you really truly aren’t sure about the process then pay to get it fixed. As mechanics, we would prefer for drivers to call rather than hatch a possibly dangerous repair. If you fry something electronic due to not being comfortable or confident in the procedures, you may have a larger repair bill!
Why do you need a ground strap?
A ground cable is the battery’s negative cable that completes a loop from the battery to the chassis. Without it, the vehicle’s electrical system can overload or short and damage electrical components in the vehicle. If it becomes disconnected, faulty, or worn, it can cause electrical problems.
What is the difference between a ground wire and a ground strap?
A ground strap is typically a braided metal strap that connects the engine to the car chassis. The ground wire or ground cable connects the negative battery cable to the car chassis. Other electronic devices may also utilize some form of ground wire as well.
Can a car start without a ground strap?
The starter motor will not receive volts to start the car without the ground cable or strap. Even if you were able to drive a distance, the car battery would not charge and leave you stranded. This is why when troubleshooting, a leaky ground strap or it shows signs of wear, it is better to start the replace of the ground strap.
How can you tell if grounding is good?
Use a digital multimeter to check the readings of the battery terminals and ground to see they are reading correctly. Then compare to your specification in the service manual to see the electrical system is running properly. If it reads bad, replace or tighten it to avoid electrical problems.
How do you install ground straps?
Remove old ground straps and connect heavy-duty cable to the negative battery terminal. The other end connects to the block or chassis. Ensure both connections are mechanically sound and clean. And ensure spent wire is of sufficient length that the ground won’t pull apart under torque.
With a bad ground strap, or loose connection, a whole host of problems can arise. For that reason, your best bet is to repair the connection at the first sign of a problem so that you don’t leave yourself stranded somewhere because of it. If you’re reasonably mechanically inclined, you might be able to dive in and replace a broken cable yourself.
Some cars are pretty difficult to get at, as the ground strap may be configured in a difficult configuration making it hard to reach the strap or grounding points. In that case, it might be easier to have a certified technician to replace it for you, unless you happen to have a little extra time on your hands, and a decent service manual to rely upon.