Maybe It’s Not Your Battery: What Can a Bad Engine Ground Cause?

If your vehicle has trouble starting or if certain electrical elements aren’t working properly, you might think your battery is at fault. However, there is another major component of your automobile that might be broken or malfunctioning: the engine ground.

A bad engine ground can produce multiple symptoms that range from a nuisance to making your car undrivable. Here’s how you might know if you have a broken ground cable and what to do if you believe that’s the root of your problems.

Image by StockSnap from Pixabay

What Is the Engine Ground in a Car or Truck?

The engine ground in your vehicle can go by several different names:

  • Ground cable
  • Engine ground cable
  • Ground wire
  • Negative battery cable
  • Ground strap

This part is an essential element of your vehicle’s electrical system. It runs between the chassis and the battery’s negative terminal. (A second ground strap lies between the engine and the body.)

Any electrical current used in your vehicle runs through the ground cable. As a ground, it dissipates electrical charges and helps prevent dangerous electrical shock.

Bad Engine Block Ground Symptoms

What can a bad engine ground cause? You name it! Any of these problems, individually or sometimes in combination, could be caused by a faulty engine ground:

Vehicle won’t start

One key symptom of a bad engine ground is a vehicle that won’t start or only starts intermittently. It’s easy to blame the battery, the alternator, or the starter, but a faulty ground cable is a feasible cause.

Wear on battery

Because your car or truck won’t start reliably, you may be jump-starting it often. That, plus uncontrolled electrical current, could be putting strain on what was a perfectly good battery. When tested, it may be low on power, or you may be told you need to prematurely replace a battery.

Flickering or dimming lights

Just like when you have low electrical power in your house or loose wires in your home’s electrical system, you can have vehicle lights that flicker or dim with a bad engine ground. This includes headlights, tail lights, brake lights, and dome lights inside the automobile.

Malfunctioning electrical components

Other components of the vehicle that rely on electrical power supply are likely to be affected by a faulty ground cable too. Examples include:

  • Radio and sound system
  • GPS navigation
  • Heating and air conditioning
  • Power window function
  • Cruise control
  • Horn
  • Power steering
  • Dashboard gauges
  • Windshield wipers

While being without your radio or cruise control is more of a nuisance, problems with your power steering, dashboard control panel, wipers, and horn affect safety.

Poor fuel efficiency

Your fuel delivery system may also be influenced by a bad ground strap. Therefore, you might be making more trips to the pump than you normally do.

Engine misfiring

Disruption of the ignition system may also cause engine malfunction. Misfiring is common, as is stalling and strange idling problems. This poses undue wear on the engine, which you want to avoid. Obviously, stalling can put you, a family driver, or an employee at risk of an accident.

Buzzing and crackling noises

Any time you have electrical current problems — whether in your home or in your car — you can often hear it. With a bad ground cable, you might notice electrical noise in the vicinity of the engine or electrical components. Crackling and buzzing are indicative of excess (uncontrolled through proper resistance) electricity or gaps in wiring associated with a loose cable.

What Causes a Ground Strap to Break or Malfunction?

There are a couple of reasons a ground strap can fail on you. Often, it’s a case of wear and tear with older vehicles or those that take a lot of abuse, like fleet and work vehicles or cars used for long daily commutes.

If you frequently drive on bumpy terrain, the ground cable attachment can also come loose. This gives the impression of a broken ground.

Ocean air (common here in Vancouver, BC) and road salt used across Canada can also cause corrosion of metal parts, including the ground cable. If you’ve had other problems due to this phenomenon, it wouldn’t be unusual for corrosion to affect your ground strap as well.

Sometimes the ground cable can be worn, loosened, or broken by animals that get under the hood. Mice, chipmunks, rats, and squirrels often take refuge in vehicles in cold weather. Look for chewed wires or insulation in other parts of the van or car too.

Fixing a Broken Ground Strap Is NOT a Do-It-Yourself Project

You might be able to look under the hood and see the ground broken. However, this doesn’t mean repairing the ground cable is a DIY job. Especially when dealing with electrical components, it’s best to have the wire replaced by a professional.

First, there’s the risk of electrical shock if you try to install a new ground cable yourself. Second, if you don’t do the job correctly, you could permanently damage electrical components in your car or truck. Is your vehicle still under warranty? You would likely void the warranty by putting in a new cable yourself.

Don’t try to drive with a bad ground cable, particularly given the safety concerns raised above. Make an appointment with your mechanic as soon as possible, both to fix the ground issue and to protect other elements of your vehicle from further damage.