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Troubleshooting your electrical system is the first step in determining why your vehicle’s lighting system appears to have gone wild. Flickering dash lights are most often caused by alternator issues.

First of all, let’s make sure your alternator is in good working order. You can take your alternator to AutoZone and they will test it for you FREE of charge. Unreliable wiring (especially ignition wiring) and bad connections could also cause such an effect.

The alternator is in charge of running your vehicle’s electrical components as well as charging the battery. If the alternator fails, it may not be able to give adequate current to all of the components on a consistent basis.

Also, check to see if your car battery is charging properly and inspect it for any signs of corrosion. While it may appear weird, it is a common problem.

The following are the top reasons why dash lighting flickers:

  1. The battery is defective
  2. Battery wires that are loose or filthy
  3. Ignition switch failure
  4. Relay failure
  5. Dash control module failure
  6. Loose connector or wiring on the dash panel
  7. Alternator failure

Now, let’s look for warning signals.  Your dashboard is more than simply a collection of warning lights, it’s a computer that handles a variety of tasks.

Your car is jam-packed with computer modules, each of which is in charge of a different system. Despite the fact that all of these modules have well-defined roles, they do not work in isolation.

They are continually communicating with one another via a communication network, and your dash panel is critical to their functionality. If your dash module goes down, the entire system goes down with it.

Here’s a more in-depth look at the most prevalent causes of flickering car lights:

1. Battery failure

How old is the battery in your car? If your battery is losing power, a low acid level could be one of the causes. The lights may flicker as a warning indicator if your battery’s ability to charge correctly is deteriorating.

Battery voltage is critical in today’s computer-controlled vehicles. When dealing with electrical problems, you should always start with the battery.

Your vehicle’s onboard computer is capable of causing the car’s electrics to behave strangely upon detecting a power problem. The battery needs to be up to the task!

A battery usually lasts 3 to 4 years. Also, you need to make sure your battery is the right size for your vehicle.

The following readings apply to your battery:

Voltage Charge
12.7 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%

2. Loose battery wires

Another very common reason for flickering dash lights is loose battery cables, which are also the easiest to fix. Locate your battery and make sure your battery terminals aren’t corroded.

Because battery acid can spill from the terminal posts, you’ll need gloves and safety glasses to avoid skin burns.
Baking soda and water can be used to neutralize white acid corrosion.

Cleaning, tightening, and coating the terminals with petroleum jelly will help prevent future corrosion. Your battery cables or terminals may also be damaged, so look for fractures or bulges in the insulator.

You’ll need a voltmeter to perform a simple volt drop test to discover high resistance in battery cables. Loose ground straps (battery to chassis and chassis to the engine), faulty wire, and corroded wiring are all common problems.

3. Problem with the ignition switch

It’s possible that your ignition switch has been worn out. Ignition wires that are NOT very well connected could be the source of the problem in your wiring.

Faulty internal components of the ignitions switch can short the ignition circuit, causing it to turn ON!

4. Relay failure

It’s probably the simplest problem to solve because all you have to do is change a relay. A relay has two sides: one for the load and one for the control.

The circuits are self-contained, allowing the control side (usually low amp) to control the load side (often high amp) without putting interior switches or sensitive circuits in danger.

Many relays are to be found in your fuse box. While at it, you may want to remove the main fuse and reinsert it several times to clean contact points.

Once the relay is removed, you can check it for continuity. You can try swapping the relay with an identical one or simply replace it (watch for matching pins).

5. Problem with the dashboard computer module

Dash modules are complicated pieces of equipment, and we won’t even attempt to comprehend how they work. That isn’t to say we can’t test or fix it.

On the power side, we can inspect power inputs, grounds, and wiring for chaffing. There will be two ignitions on your module, as well as a power supply for the logic circuit.

It’s also crucial to inspect the ground. To find high resistance, use a volt drop test.

The dash module is difficult to reach, and higher-end vehicles may require specific tools. Other components, such as the airbag and steering wheel, may need to be removed as well.

6. Loose dash panel connectors

Depending on your vehicle’s onboard computer system, any ground connections that are not entirely secured may cause trouble with flickering lights in your dashboard. It could be caused by anything from wobbling bolts to other intermittent connections.

In cars lacking modern cam-lock block connectors, loose block connectors at the back of the dashboard are typical. To check for any changes in condition, wriggle the wire and block connectors systematically to see if the problem is solved.

7. Problems with the alternator

Flickering car lights are frequently caused by a problem with the alternator in your vehicle. If one of the three rotating plates that create power for your car or truck is worn out, your lights will flicker.

For a variety of reasons, a malfunctioning alternator is bad news! It may prevent your battery from charging sufficiently, gradually draining it to the point where you’ll require a jump start to restart.

And, because the spark is created by electrical current flowing through the spark plugs, if the alternator fails completely, your engine will stop functioning sooner than later.

Once again, AutoZone offers a free battery and alternator testing service. You can also go to any dealership or local shop (see map below) to get them tested as well.

In some cases, replacing the alternator will fix this type of problem:

Here is another good article “How to Diagnose & Fix Charging System Failure” that can help you out.

This article is for informational purposes ONLY and is NOT a replacement for professional advice!


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