Miata headlight bulbs not burning the midnight oil - why?

September 23, 2010 2:18 PM

Why do the light bulbs on my Miata keep burning out?

I've got a 2000 Mazda Miata, which I bought new, and now has about 70,000 miles on it. Ever since I've owned it, the light bulbs in the headlights have burned out at a stupendous rate, like a pair a year, or even more often than that. I took it in to the dealer while it was still under warranty and complained, and after an examination of the car's electrical system got essentially a shrug. The problem has continued.

I've tried multiple kinds of bulbs, from the super expensive to the super cheap, and they all die early deaths. I've gone though easily a dozen pairs on this car, while my husband's car has never had a bulb burn out in the same period.

Any idea what the problem is, and how I could possibly fix it? And if I can't fix it, what kind of bulb would you think would be the best to buy, the cheapest? Is there an environmental consideration when buying a bulb that I know is destined for the landfill in a year?

posted by Capri to travel & transportation (18 answers total)

Next time you buy bulbs, get a wiring set with the bulbs, and replace everything together. This can get expensive, however, but the connections on this wiring can get awfully corroded, too.
posted by Cool Papa Bell at 2:24 PM on September 23, 2010

FWIW I go through three sets of bulbs a year in my 2004 Civic LX. I use the lights whenever I drive the car and put about 35,000 miles a year on it (currently at 130,000). I only buy the cheap ones, though, since the more expensive ones do not last longer in my car.
posted by vkxmai at 2:35 PM on September 23, 2010

sounds like you've got a short. My radio on my miata would stop playing (and lose it's security code) every time it rained. In my case it was a bare wire touching the frame of the car. It's an easy fix once you know what you're looking for. you might be able to fix it with some electrical tape, if you can find it. good luck!
posted by ChefJoAnna at 3:04 PM on September 23, 2010

I can think of three things, as someone who has always driven with his lights on even during daylight hours, and has never had bulbs burn out like you're describing.

1. The voltage regulator is sketchy, and the surges are killing the bulbs.
2. The roads you drive are very rough and damage the bulbs at a surprising rate.
3. The headlight design is flawed.

Rule out #3 by visiting Miata forums and asking other people with the same model year, and rule out #2 by taking stock of the roads you drive on. #1 will require a mechanic's diagnostic, and may also be a design flaw (again, ask on the boards.)
posted by davejay at 3:04 PM on September 23, 2010

my tail light cover had a small crack in it which let a small amount of water into the enclosure when it rained, and the tail light blew out after nearly every rain storm as a result until i determined the issue.
posted by radiosilents at 3:45 PM on September 23, 2010 [1 favorite]

Miata.net is your friend. http://forum.miata.net/vb/
posted by GeeEmm at 4:04 PM on September 23, 2010

I don't see how a short can cause a bulb to burn out. A short would deliver less current to the bulb, causing it to not light but certainly not burn out out. Also, it would burn a fuse or start a fire.

Most likely you have a mechanical issue, like the bulbs are taking hard knocks due to poor mounting hardware or they are getting hit with gravel. Overvoltage might be a problem too.

So I'm Nthing davejay.
posted by chairface at 4:21 PM on September 23, 2010

I don't know if this is a general Mazda trait, but my friend and I had matching 2005 Mazda Protege hatchbacks for a while, and our headlights burned out every 6-9 months. It was crazy, but we both got crazy good at replacing them (especially in winter).

For completely different reasons I swapped out the Protege for a Honda Civic, and every time I turn on my lights I marvel the fact that I haven't had to replace them yet. It's like magic!
posted by Maarika at 4:59 PM on September 23, 2010

do other bulbs blow? if not it's not the voltage regulator......I had a overcharging alternator once (bad VR), disconnected the battery because it was boiling & POW every bulb in the car blew!
posted by patnok at 5:24 PM on September 23, 2010

Thanks for all the brainstorming. A few posts have asked questions, so here are some answers.

- The only other bulb to go out is on the dashboard (and if anyone knows how to replace that, I'd love to hear how -- and oddly two of the three bulbs in my husband's Mazda's dash have also gone out).
- The car is ten years old, and the problem has been happening the whole ten years, so I don't think it's corrosion.
- It has happened in the three very different places I've lived with the car, so I don't think it's the roads.
- It only has 70,000 miles on it, so I don't think it's from having them on excessively (although I do drive with my lights on most of the time).
- They don't both go out at the same time, so I am kind of guessing that it's not a voltage issue, but as my husband will readily tell you (with disdain) I managed to get through undergraduate and graduate school in the sciences without ever taking physics, so I could be wrong there.
- There's a lot of rain where I live, in the Pacific Northwest, but I've never seen water in the headlight casings, and haven't noticed any rain-related patterns of dead bulbs.

It seems like I'm getting down to poor mounting (and hence physical trauma to the sensitive little dears) or karma payback for something I said to an ex-boyfriend at some point which wasn't entirely deserved. Maybe the time Mike berated me for treating him like a child, and I calmly pointed out that his shirt was on backwards? No, I think that was deserved...must have been something else.
posted by Capri at 6:05 PM on September 23, 2010

There don't appear to be any technical service bulletins on overheating bulbs. I have a '96 but that's a NA model (pop-up headlights instead of integrated) but I can attest to the build quality of the Miata in general. You probably know this already but if the bulbs are touched at all it can negatively affect their lifespan dramatically.
posted by Civil_Disobedient at 6:05 PM on September 23, 2010

If you get the oil from your fingers on the halogen bulbs when you change them, their life span will be shortened.
posted by Daddy-O at 6:35 PM on September 23, 2010

It sounds like it's a vibration issue with this car vibrating the bulbs so much that they fail. You could try opening the hood and wiggling the headlights to see if the mounts are loose.

I live in the Northwest, and I saw a local mechanic advertising High Intensity Discharge headlight conversions for most cars from $150. Maybe, just maybe, HID headlights might be more tolerant of vibration than regular bulbs.
posted by monotreme at 7:00 PM on September 23, 2010

I never touch the glass on the bulbs, and I've shaken the housings and they don't move. I just don't get it. I'll look into the HID option. Thanks.
posted by Capri at 7:34 PM on September 23, 2010

My 99 Miata didn't like the expensive sylvania bulbs, which burned out quickly too. My cheapo replacements have been just fine, though most of my driving is daytime without them on. You really should check miata.net as there are numerous posts on lighting. Good luck.
posted by pappy at 7:48 PM on September 23, 2010

My 2000 Miata never went through bulbs like this.
posted by BryanPayne at 12:14 PM on September 24, 2010

I don't know if this is a general Mazda trait, but my friend and I had matching 2005 Mazda Protege hatchbacks for a while, and our headlights burned out every 6-9 months. It was crazy, but we both got crazy good at replacing them (especially in winter).

I think this is either a 2002 or 2003 because they only made the hatchback for two years (the Protege5).

Either way I was going to post this same anecdote. Our 2003 Protege5 goes through bulbs pretty fast, and if you check some of the mazda/protege forums it is a known problem. They are very easy to change after the first couple of times. No tools are needed.
posted by Big_B at 3:17 PM on September 24, 2010

@ Big_B, et al - yes, it was a 2003 Protege 5... Sorry for the typo!
posted by Maarika at 5:53 PM on September 28, 2010