Why Do Headlights Burn Out So Frequently?

July 25, 2007 – 9:03 am by Matt Radel
Filed under Car Care

Back at the end of April I wrote in disgust about my second headlight burning out within a matter of weeks. Why do they burn out? One of our readers, Negative Ed, was kind enough to write in and explain:

First off, the H7 bulb is essentially a small spring in a glass tube. When said spring has electricity passed through it, it lights up, AND produces large quantities of heat. Now you have a small, HOT spring. If you shake that small, hot spring, it breaks.

What constitutes ’shaking’? Hitting a big pothole will cause the lights to break if they’re on. Closing the hood with the lights on will do it too. And the issue is compounded when it’s ULTRA cold out. I know. I found out the hard way when I closed the hood of my Golf at 5am on a cold February morning… and had two brandy new Silverstar lights blow at the same time.

I have been very careful since that day and have had my lights last MUCH longer now.

Great info. I’ll be more careful with my headlights from now on.

Why Do Headlights Burn Out So Frequently?
July 25, 2007 – 9:03 am by Matt Radel