You put your key in the ignition, only to hear a clicking sound. You turn on your headlights, and they seem to be dimmer than usual. These and more may be signs that your electrical system is having some issues. Before going out and purchasing a new battery, there are some measures you can take to make sure it is the battery, and not just a faulty wire or poor connection.
Here are some steps in troubleshooting your vehicle’s electrical system:
1. Diagnostic Tools
There are a couple of diagnostic tools that are necessary to get an accurate reading of your vehicle’s electrical system. You need both an ohmmeter (which measures electrical resistance) and a voltmeter (measures the electrical difference between two points in a circuit), or you can get a multimeter that has both built into one unit. You will use this tool to measure the battery, the alternator, and the voltage load points at different sections of the car.
2. Load Points
Load points, or contact points, are where the loads (lightbulb, ignition, etc.) receive power. If your windshield wipers seem faulty, for instance, it could be that the voltage at that point may not be reaching the minimum threshold voltage necessary for it to function correctly.
If this is the case, it may be one of the following problems: excess resistance (test with the ohmmeter/multimeter to see if this is the case), low or no voltage, circuit discontinuity, or burnt out wires.
3. The Battery
The battery is the most obvious culprit. Your car battery should be replaced every 4-7 years, so if it’s around that time – that may be why things aren’t working as well as they used to. To check the battery output, you need to disconnect it from the car. The PCM (powertrain control module) will likely reset it’s programmed settings when you do this, so attach a 9V battery to the PCM for a seamless transition.
With your multimeter, you can test to see if your battery is holding a charge. If the voltage reads approximately 12.43 V, your battery is working/ charging. If it’s higher at around 12.66 V, your battery is at maximum charge. However, if it’s less than 12.43 V, you need to charge your battery. If your battery is over a few years old, it’s possible that it won’t function at its peak anymore and may ultimately need replacement.
4. The Alternator
If your battery seems to be working fine, then the next step in diagnostics is checking out the alternator.
Start the car and raise the RPM levels. Look at the alternator voltage output reading: it should say a range between 13 V to more than 14 V. If you see that the engine is running at around 2000 RPM, then the alternator is fine. If it drops below 13 V, then your culprit is likely the alternator after all. It may need to be checked out to see if something is loose within the body or needs replacement altogether.
5. Reconnect The Battery to Check the Load Points
If your battery is running well, and the alternator is working fine, your next step is to check the load points individually.
After reconnecting the battery, check the voltage at the load points of the parts of the car that aren’t working. If you find that the voltage is very low or even zero at a specific load point, it’s possible that the fuse burned out or the relay switch isn’t working.
If you find a weak load point, check the surrounding grounding. Since the circuitry is in a metal casing, if the grounding is the issue, then the electrical current wouldn’t work.
6. Check The Wiring
If everything else is working correctly, it may be the wires themselves. Corrosion or malfunction is a common problem. If you look at a wiring diagram for your vehicle, it will assist you in understanding which wires serve what purpose and you can have a better read on your car’s diagnostics. Using the voltmeter, check for faulty wires by seeing if there’s a voltage drop between two connected wires. If the decrease is more than 0.1 V, you will have to replace the wire. Check continuity by measuring the resistance between both ends of the connection of the wire with the multimeter. If the wire reads infinite, it requires replacement.
7. Water Damage
If everything seems to be working correctly, the last thing to check is the end device. Water exposure to any electrical circuit (usually due to rainwater seeping on to circuitry) can generally lead to short-circuiting.
Troubleshooting your vehicle’s electrical system may seem intimidating at first, but with enough practice and hands-on experience, you’ll be able to perform periodical checks over time. This will help prevent any issues creeping up unexpectedly. If your alternator needs replacing or a large-scale repair, you may want to leave that to professionals such as Inland Alternator. However, with your knowledge of how your car circuitry works, you’ll save the worry of guessing and diagnose the problem ahead of time.