A How to Guide in Diagnosing Your Auto Electrics

For a reliable and safe operation of your car, every vehicle depends on a fully functional electrical system. Sure it needs fuel to run efficiently and yearly checks to keep things operating smoothly too, but without healthy auto electrics you won’t be getting anywhere too quickly.

When it comes to diagnosing electric problems in your car, it can be one of the most frustrating and expensive issues. And not just to diagnose – but to repair too. From dreaded battery dramas to faulty switches and connections, it’s a good idea to familiarise yourself with the electrical system basics to effectively start your car’s engine, power the headlights and run most of the safety systems within your vehicle. Here are some auto electrical diagnosis tips for the most common problems.

1. The Battery vs. the Alternator

On average, a car battery should be changed around every 3 years. If you find you’re having issues with it before then – chances are, your alternator isn’t working or connections in the electrical control unit have been disabled. Driving style and extreme heat can play a big role with the life of your car battery too. If your car is having problems starting inspect the battery first and check all cables are properly connected. You can use a voltmeter to connect to the red wire which will test its voltage level. Volts between 12.5 and 12.8 mean your battery is fine.

The alternator is what charges the car’s battery and keeps it running, but only when the engine is running. If you find your car is ticking over, but not actually starting – this can be a sign the alternator is failing. You’ll notice some of your car’s accessories like the radio and lights won’t be working or dull. If you have replaced the battery or the battery is new but won’t keep charge, the problem almost always lies with the alternator and needs replacing.

2. Low Voltage

Some car electrical problems can be diagnosed by tracing voltage drops. Dim headlights and slow starting can be a sign of low voltage and occurs when a car’s component isn’t receiving power to run or simply not at the required voltage for operation. Low voltage is usually caused by a connection issue or improper grounding networks which causes the voltage to drop below what it should be at.

Voltage levels will drop when wires are worn out and corroded and will require replacing to work effectively again. Voltage drop testing can be done to find exactly where the electrical fault is and will find where the disruption is within the electrical circuit. Unless you’re an electrician, it’s best to have a professional mechanic to run a voltage drop test, but you can start by checking the wires and connections for possible corrosion or worn out parts.

3. Grounding Connections

Ground circuit problems are the plague of car electronics. When a ground circuit cable or connector gets loose, it causes the voltage levels to drop and your vehicle’s components to shut down. Loose wires can happen from heat, shortened life or the vibrations from every day driving and can lead to various problems.

The metal body of your vehicle serves as the ‘ground’ and is required to connect each part of your car’s system to the battery. Each of these components are connected by the grounding system. Check the vehicle’s wires and connectors and tighten to help resolve the problem, or cleaning them can assist in solving many grounding issues.

4. Blown Fuses

Another common problem for things not working within your car is a blown fuse or two. This can shut off your headlights or electric windows, or completely stop your vehicle functioning all together – depending on what fuses have blown. Your owner’s manual will lead you to the fuse panel of your car (there may be more than one) and it’s a fairly simple process to diagnose, find and replace it yourself.

If you are able to find the blown fuse, use a small pair of tweezers to pull it out. You’ll see that the strand of metal that passes between either sides will be broken. It’s vital to replace any broken fuses with one that has an identical amp rating. This will be colour coded and listed. If you have a car with no electrical power, a good battery and a working alternator – chances are one of the main fuses has blown.

5. Starter Motor

Bad starter motors can be caused by poor maintenance or regular wear and tear. And without an effective starter motor, your car will not start! Starter motor problems can be anything from slow-cranking conditions or no-crank at all and can be a result of bad electrical connections or an undercharged / failed battery.

Paying attention to your vehicle’s sounds will help to indicate whether the starter motor is playing up. New sounds, like buzzing, loud clicks, whirring sounds or grinding noises may mean there’s loose mounting bolts in the motor or poor electrical current flow. Check for corroded battery terminals and run a battery test to eliminate that being the issue.

Whilst this list can help you troubleshoot any potential auto electrical problems, it’s thoroughly advised to seek professional mechanical help. At Autospark, we are fully qualified in diagnosing auto electrical issues and with the latest technology, can assist in getting your vehicle up and running again.