You might be working on your car and find that no ground connection is available nearby for the ground wire.
If that’s your situation, you’ll want to know what to do. Should you leave the ground wire and tape its end or connect it somewhere else? Why is the ground wire even necessary? Can you still use the car without connecting the ground wire?
This article answers all these questions. It tells you exactly what you should do with the ground wire if there’s no ground.
If no ground connection is available for a ground wire, create one. It’s important that you do, as the ground connection is necessary to complete the circuit and ensure all the car’s electronics can function normally. Choose a bare metal (non-painted) spot that is clean, secure, rust-free, corrosion-free, and has low resistance (below 0.2 volts).
The Ground Wire and Connection
The ground wire is the black or negative wire from the car’s battery.
It is connected to the battery’s negative terminal. The other end is attached to a ground connection, usually a bare metal part of the car’s body (chassis) or engine.
An alternative is possible, called an “insulated return,” but it’s usually only arranged for petrol tankers, as they transport highly flammable content.
The ground wire of some components may be brown instead of black, so look for either.
Purpose and Importance
Forming a ground connection for the ground wire is important because a car’s electrical circuit is a closed-loop system.
The ground point, such as the chassis, acts as a conductor between the battery’s positive and negative terminals. When you connect the two battery terminals and the circuit is complete with a load, the pressure difference between them generates an EMF (electromotive force) to drive the electrical current.
This system flows from the battery’s positive (+) terminal to its negative (-) terminal. All the car’s electronics are connected to and rely on this loop. A continuous and uninterrupted flow of electricity is essential for them to function normally.
A Bad or Missing Ground Connection
A bad or missing ground connection cannot provide a continuous and uninterrupted flow of electricity, which is necessary for all the car’s electronics.
Consequently, the current tries to create another return path to the battery ground. The disruption or diversion from the normal flow often causes various electrical problems.
Common symptoms include electronic glitches, flickering headlights, low alternator voltage, engine misfires, heavy cranking, etc. Although it might not drain the battery, it can cause it not to charge properly and the car to give wrong signals.
It can cause hard starts, weaken or malfunction the spark plugs, and create problems in the relay or heaters (in a diesel engine). A bad ground connection can even cause a car not to start. It can affect a car’s electrical system, including its sensors and coils, and severe damage may require costly repairs.
In short, a proper ground connection is critical for the car’s electrical system to function properly.
Creating a Ground Connection
Usually, the vehicle’s manufacturer creates a factory-set ground point. But if, for some reason, there’s no suitable ground spot nearby, you will have to create a new one. Here’s how to do that:
Step 1: Choose a Suitable Spot
The ground connections (at both ends) must be bare metal (non-painted), clean, secure, rust-free, and corrosion-free.
The surface chosen for grounding should not be anodized because it is not a good electrical conductor, so it will not provide proper ground.
Step 2: Test the Ground Spot
See the next section on testing the ground spot using a multimeter.
It’s important that you test the resistance at the spot first before drilling a hole there. It must have low resistance (less than 0.2 volts).
Step 3: Drill a Hole
Drill a hole in a suitable spot for the new ground connection.
Remember that it must be bare metal (non-painted), clean, secure, rust-free, and corrosion-free.
Step 4: Clean the Spot
Although you chose a clean spot, to begin with, clean it further after drilling the hole.
Use WD-40 and a wire brush or sandpaper to clean the spot this time. This is to ensure we get a good connection with the bare metal.
Step 5: Apply Grease or Jelly
Apply either some grease or petroleum jelly to the hole’s top and underside.
Step 6: Set the Nut and Bolt
Place the nut and bolt into place for the new ground spot.
Hold the nut at the bottom, place a washer on the top, and insert a bolt through the hole. Let the bolt pass through but don’t tighten it just yet.
Step 7: Attach the Ground Wire
Attach the ground wire with a spade connector to the underside of the bolt’s head, below the washer (on the top part of the chassis, as shown in the above picture). Then, tighten the bolt.
The new ground connection should now be ready, but we should ensure it’s good before using it.
Check the Ground Connections
Ensure the following after creating a new ground connection:
- The contact should be secure. Vibrations can loosen the ground connections if they’re not secure. Tighten them if you notice any loose contacts, or replace them if their threads are damaged.
- The wires, cables, straps, and connectors should not be damaged. Even if the point where the ground wire is connected to the chassis is secure, any damage before that point will also cause a bad ground connection.
- Rust and corrosion. These two also weaken a ground connection even if the nuts and screws are tight. Water is the main cause of rusted metal, and corrosion on the battery’s terminals is caused by sulfuric acid producing hydrogen.
The above applies to both ends of the ground wire – not only the new ground connection spot you created but also the point from where the wire starts and all along the way.
Test the Ground Using a Multimeter
A proper check to see if the ground connection is doing its job requires a multimeter.
Step 1: Set the Multimeter Up
Set the multimeter to DC volts. It should cover the range of up to 16 volts.
Step 2: Disable the Ignition
Disable the ignition and set the gear to neutral.
Step 3: Connect the Probes
Connect the black probe to the battery’s negative terminal and the red probe to the new ground connection spot on the chassis.
Step 4: Crank the Engine
Crank the engine to get a reading.
Step 5: Check the Reading
The voltage should not exceed 0.2 volts; otherwise, the resistance is too high. Choose another spot where the resistance doesn’t exceed this value.
A significant variation in the voltage between two points means there’s a high resistance somewhere between them. Inspect that area for any loose or broken connectors, wires, rust, or corrosion. Either fix the problem or change the electrical ground connection spot.
A damaged ground strap. https://www.gomog.com/starter.htm
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