Why Does My Headlight Bulb Keep Blowing

In this article, we’re going to look at the reasons your headlight bulb keeps blowing.

Changing lightbulbs on vehicle headlights is easy as pie – mostly. It doesn’t involve much more than removing the back cover, slitting a new bulb in, and reassembling, right?

 The problem arises when newly replaced light bulbs keep on blowing. It is at that point that troubleshooting becomes a bigger effort than replacing the blown bulb.

 We’ve put together a list of reasons why your light bulb may be blowing incessantly, and also a few quick fixes to prevent it from happening in the future. Keep reading!    

Why Your Headlight Bulb Keeps Blowing

The list of reasons that follow should be at the top of your checklist if you have a problem with a headlight bulb that blows all the time.

  1. A faulty voltage regulator or alternator – This is a critical piece of equipment on your vehicle. It limits the maximum voltage that flows through the electrical system on your car and keeps it at a safe level. If the regulator has a problem and the voltage starts spiking, this is a surefire way for lightbulbs to blow.
  2. Loose wiring connections – If you have loose connections, it could cause intermittency, and this in turn could lead to lightbulbs blowing. If your vehicle is prone to vibrations, it could exacerbate the problem.
  3. Poor quality bulbs – if you’ve replaced the bulbs in your headlights before, and tried to save a few bucks by getting a dubious import from a country you’ve never heard of, this could be your issue. Poor-quality light bulbs have poor-quality filaments. They don’t last.
  4. Oily residue on glass surface – if you managed to touch the glass part of the headlight bulb when you installed it, the oily residue left behind by your fingers could cause the bulbs to blow. Wear a cotton glove when replacing the bulb, and this problem will be sorted.
  5. Excessive vibration – Halogen filaments are especially prone to this. If you drive on rural roads, or your car’s wheels are badly out of alignment, the consequent vibrations could shake connections loose, and the intermittency could cause the bulbs to blow.
  6. Too much condensation in the headlight – this is an issue in wet or tropical climates. When the water condensates in the headlight housing, it can seep into the lightbulb and cause a short. That will blow the bulb every time.

How To Prevent A Headlight Bulb From Blowing

Prevention is better than cure every single time. Here is a list of things you can do to prevent your headlight bulbs from blowing.

  1. Headlight bulbs typically last for around 400 hours. If you do a lot of night driving in winter, or even if you use your headlights as a safety precaution during the day, the extended hours will shorten the lifespan of your bulbs.
  2. Don’t touch the glass of the bulb when you change them. The oily residue left behind by your skin will create a hotspot on the bulb, and this could lead to early failure. Wear latex gloves when you replace your headlight bulbs – this will solve the problem.
  3. One would think that a “vibration-proof” lightbulb for vehicle headlights would have been invented by now. Seeing as vibration is a headlight bulb’s number one enemy. Vibration becomes doubly dangerous when there is excess moisture in the headlight housing because the glass of the bulb could shake loose from the base and create micro-pores through which moisture can reach the filament and cause a short. Secure installation is your only preventative measure for this one. And making sure your headlight casing is well sealed.
  4. Make sure your electrical system is checked when you have your car serviced. Minor electrical issues can cause voltage fluctuations, which will blow your headlight bulbs.
  5. When you do replace your lightbulbs, it pays to opt for something that comes from a reputable brand. Cheap and nasty won’t last in this case.

Can A Blown Headlight Bulb Be Fixed?

It can. It’s one of the simpler automotive maintenance jobs there is. It only takes a few steps and around ten minutes. And you can do it without any technical know-how. Your owner’s manual should have a section on replacing your headlight and taillight bulbs.

A parting shot

It’s slightly ironic that one of the easiest parts of the car to maintain in good condition – the headlights – is often the one thing we ignore. And yet, the headlights are critical for both safety and driving comfort.

 It’s also something you can maintain by yourself, without needing any technical skills. Go ahead – check them out, and make sure they’re in safe, working order!

Check out our most popular pages to find the best headlight bulbs.

Check out the brightest headlight bulbs as well.

Photo of author

Richard Nickleson is the author and owner behind Headlight Reviews. He first started the site as a hobby to share his insights on car parts and specifically headlight bulbs, but it soon ballooned and now he writes on all topics surrounding headlights bulbs. If you've got a bulb question, contact Richard here.