"Gremlins" might seem like an outdated term, but it still has its place in the modern automotive world. Mechanics and automotive enthusiasts often use this phrase to describe unusual and seemingly unconnected electrical problems. In other words, your car's behaving as if mischievous gremlins are hanging out in the electrical system and wreaking havoc.
Of course, the real cause of these problems is typically far more prosaic. Modern cars use complicated electrical and electronic systems, and small problems can result in numerous and apparently unrelated symptoms. Why gremlins are, by definition, hard to track down, this guide will explain three of the most common causes of these frustrating electrical problems.
1. Charging System Failure
Your charging system consists of your alternator, battery, and the various wires and electronic components that help manage and connect it. You need your battery to get your engine turning, but the charging system continues to function while the car is running. Not only does the alternator keep your battery charged, but it also supplies power (via the battery) to your car's electronic accessories.
However, an electronic accessory is a broad term in modern vehicles. Many critical systems that were once belt-driven, including items such as your power steering pump, may now run on battery power. As a result, a faulty alternator or a failing battery can cause many potential problems throughout your car. In most cases, these items will be the first culprit when tracking down pesky electrical gremlins.
2. Accessory Belt Slippage
While modern manufacturers are converting more and more engine systems from belt-driven to electric, it's still necessary for your alternator to pull power directly from the engine. The accessory belt connects your alternator (and several other components) to the engine's crank pulley. This connection allows the alternator to convert mechanical energy into electrical power.
Belts can wear out over time, usually producing a noticeable squealing noise as they slip on their pulleys. This effect can reduce the alternator's power output, leading to noticeable symptoms such as dimming lights or unusual failures in interior electronics. Note that slipping belts aren't always routine maintenance issues — in some cases, problems such as oil leaks can cause an accessory belt to slip.
3. Grounding Problems
An electrical circuit can't work without a complete path to the ground, and grounding problems are common as vehicles age. Your car most likely uses a heavy-duty cable that runs from the battery's negative terminal to the chassis, providing a solid ground connection. Over time, this connection can corrode or loosen, resulting in a poor connection.
Grounding problems often lead to intermittent problems as the cable shifts or loosens. Some electronic components may also be more sensitive to these issues than others, causing problems that appear (at first glance) unconnected. Diagnosing and locating a grounding fault can be tricky, so this job is usually best left to a professional auto repair shop.