Cars used to be entirely mechanical, but as technology advanced, the many mechanisms in cars have been replaced with electronics, from fuel injectors and on board computers to infotainment systems and seat adjusters. When electrical components fail or malfunction, it can be extremely problematic. While most major electrical repairs should be handled by certified technicians, there are ways for amateur mechanics to troubleshoot the issue and at least find out what is going on. In many instances, a minor issue such as a damaged wire or a blown fuse can be handled at home.
Safety tips when troubleshooting electrical problems
You will need to be careful when diagnosing electrical problems, and if you decide to make the repairs yourself, you'll want to disconnect the battery first. Most electrical components in your car operate at low voltages that do not present any real danger to you. However, the ignition system does operate at a higher voltage and should be approached cautiously.
Finding the problem
You can use the owner's manual to find more information about a particular power circuit. Many circuits are connected to multiple electronics. This information can help you determine if an issue is related to a specific device or stems from a problem with the overall circuit. If other devices in the circuit are working properly, the wiring that connects the troublesome item could be faulty. On the other hand, if the other items on the circuit are also failing, you'll likely need to check the entire system to determine where the problem is located.
Check the fuse first
When an electrical component is malfunctioning, you should first check the fuse. If the fuse is damaged, you should replace it. In many cases, a blown fuse is the result of a singular power surge. Sometimes the damage to the fuse indicates a more serious underlying problem and you'll find the fuse will blow again soon after you replace it if this is the case. While this may be frustrating, it also helps narrow down the list of possible problems. A blown fuse means the problem is likely between the fuse and the power source.
Using a volt test light to find problems
You can use a volt test light or a voltmeter to determine whether electricity is flowing through the circuit. A voltmeter will supply you with more accurate readings, but a light is good for quick tests. A 12-volt test light can be used to check the voltage at different points along a circuit. The tool has a wire that will need to be attached to a ground. Then you can take the device in hand and touch it to the various positive points, using the owner's manual as a guide. To make sure it works, touch the end of the test light probe to the positive terminal of the car battery. It should glow brightly. You should get the same response along a circuit. If you encounter a dim light, a flicker or no response at all, you've found the troublesome area.
Using a voltmeter
While a test light lets you know power is flowing through a source, the voltmeter indicates exactly how much electricity is getting through. A voltmeter has positive and negative terminals that connect to the positive and negative ends of a circuit. Once connected, the device will provide a reading of exactly how much electricity is flowing through the circuit, allowing you to diagnose potential problems.