How Do You Know If It’s the Bulb or Ballast When Your Car’s Bulb Goes Out?

 How Do You Know If It’s the Bulb or Ballast When Your Car’s Bulb Goes Out?


Are you experiencing problems with your cars lighting system? Do you feel frustrated and can no longer enjoy a ride in peace? Well, the problem could be your bulb or ballast. But the big question is, how do you know if it is your ballast or D2R bulb that has developed issues?

Well, you need to take time and troubleshoot your headlight to figure out the real problem. It could be your bulb is at the end of its life, or it could also mean the ballast is to blame.

In this post, we will help you understand when to blame it on your bulb and when to blame it on the ballast. Before we dive deep into our discussion, let us first illustrate how the ballast system works.

What Is HID Ballast?

 A ballast is a crucial component of your entire headlight system. Its primary purpose is to control the intensity of your car headlight. It also controls the intensity of the bulbs so that they are not using up all your power.

It is like a transformer that converts your battery voltage into an appropriate amount of power required to keep your headlights on. The ballast is designed to detect bulb shutdown.

If your D2S bulb turns off, the ballast will automatically restart it within a microsecond. This happens so fast you may not even realize that your bulb shut down in the first place. But, as your bulb ages, it may turn off more often.

That can happen as many as 20 or 30 times per minute. When it gets to this point, the ballast tends to overheat. To protect itself from damage, it will shut down instead of resetting itself.

At this point, the only way of resetting your ballast is by turning on your headlight switch. If you are forced to reset your ballast repeatedly, then that could be a sign of a bad HID or LED bulb.

HID ballasts also serve as DC to AC converters. Since your headlamps cannot run on direct current (DC) supplied from the battery, they pick up the DC and converts it to alternating current (AC).

Is It a Bulb or Ballast?

Now that you know the primary function of the HID ballast, it is time to establish the cause of your lighting problems. How do you know if it is the bulb or ballast? Let us find it out:

Signs of Ballast Failure

There is a good chance that your ballast is the cause of your lighting problems if your headlights are dim, changing colors, buzzing, or flicker.

When inspecting it for potential issues, any burn marks, leaking oils, or swollen casing are indicators of failure. If you are still not sure if your ballast has taken a hit, then you need to order a new D2S bulb or D3S bulb to try it out. This is a trial and error method that may or may not work.

Once you have the new bulbs, take your old bulbs out and replace them with the new bulbs. If the new bulbs fail to light up, then the ballascould be the culprit. However, if they light up, then you already know the culprit.

You can also try to use a multimeter set to measure resistance generated on your circuit. A multimeter is a simple device designed to measure electric current, voltage, and resistance over several ranges of value.

A standard multimeter combines the functions of an ohmmeter and a voltmeter. A multimeter can either be analog or digital. To establish if your ballast is dead or not, connect one probe of the multimeter to the live wire of your ballast and the other one to the neutral wire.

If your ballast is not dead, the needle on an analog multimeter will move to the right across the measuring scale. Otherwise, the needle won't move at all.

If you are using a digital multimeter, then you need to take note of the reading displayed on the screen. If the device displays "1", it means your ballast is dead. Any other value is an indicator of good ballast since there was some resistance detected.

But, this method may be a little bit tricky since it tests your understanding of electricity and ballast specifications. It also requires great analytical skills.

Common Causes of Ballast Failure

In most cases, ballast failure occurs as a result of the surrounding environment. Heat and moisture are great enemies to your HID ballast. When it is too cold or too hot, the ballast can burn out or fail to start headlights.

A combination of heat and constant condensation can also cause severe corrosion over time. You can avoid this problem by removing and cleaning the various parts of your ballast casing and electrical board.

However, you need to be cautious and sure of what you are doing to avoid causing more problems. A slight mistake and you will be looking for a new ballast.

Signs of a Failing or Bad Bulb

If your diagnosis shows that your ballast is working fine, then the problem could be your D3S bulb. Here are some of the common signs that your headlight D2R bulb is bad:

  • Dim headlights
  • Headlight bulb flickering quite frequently
  • Headlight bulb gives off a dim pink glow
  • Constantly blowing fuses
  • Low beams don't work fine, but high beams do
  • None of the headlights is working fine

Headlight bulb diagnostic tip: Try swapping the problematic bulb to the opposite side of your car. If it works fine without turning off, then the problem could be your ballast or igniter and not the bulb.

Underground Lighting Has a Solution to Your Headlight Problems

Based in Southern Florida, Underground Lighting has been the leading supplier of car lighting systems for many years. We supply quality HID ballasts, LED bulbs, direct replacement bulbs, LED strobes, and much more.

We ship across the world and offer free shipping for all orders above $99. So, no matter where you are located, you can always choose Underground Lighting as your trusted automotive lighting store. Contact us today for inquiries and expert advice!