Mazda Protege5 headlight problem

I have a friend who has a Mazda Protege 5 (year?) that keeps burning out Sylvania halogen headlight lamps. He has measured the voltage at the socket and it is 14.3 volts. He doesn't have a service manual to indicate what the spec maximum voltage should be from the alternator should be. Any ideas, anyone???

Reply to
n9ejs
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14.3 is good; what kind of bulbs is he using? Not some of those blue-tinted things, is he? Those do have notoriously short life, the fix is to switch to a better bulb...

nate

Reply to
Nate Nagel

14.3v measured at the socket with the bulb disconnected is pretty normal. If your friend is buying the overhyped Sylvania Silverstar bulbs, that would explain it; their rated life is *extremely* short. Inspect the burned-out bulbs. If there are spherical little globs of metal at the broken ends of the failed filaments, or rattling around in the bulb, then the failure is probably due to an overvoltage condition, either steady-state or transient (spike). If there are no globs of metal, then the bulbs are likely failing due to vibration. In the latter case, carefully inspect the retainer clips that hold the bulbs into the headlamps. Re-bend as necessary to exert more tension on the bulb so it can't rattle around in the headlamp.

DS

Reply to
Daniel J. Stern

OK guys thanks for this help. I relayed it to him, and he checked the bulb and sure enough it has the burned "glob" look, and it sounds like it's the short-life bulbs that you describe he's using, but he likes them, so he's going to try and go to the trouble and put a resistor in line to reduce the voltage a little bit. Stand by for the next exciting chapter!

Reply to
n9ejs

hmmm....

lessee here. Your friend put blue tinted bulbs in his car because he thought they would help him see better. He found that due to the blue tinting the mfgr. had to put in a smaller filament to get acceptable light output, with subsequent short life. Now instead of giving up on that experiment and going to a good, high-output white bulb like DS recommended, he's going to drop the voltage to the headlights in an attempt to make them last longer, so instead of being blue and short-lived they will be blue and dim. Keep in mind that incandescent bulbs are very sensitive to voltage fluctuations, a drop of a volt or two will cause a significant loss of light output (I personally have gone to some lengths to ensure that the H4s in my car are being fed their recommended daily allowance of electrons.)

Not to be mean, but it sounds like your friend needs a biatch-slap and a pair of Xtravisions.

A possibility that your friend doesn't seem to have explored is that the voltage is spiking; does a Protege5 have a voltmeter in the dash?

nate

Reply to
N8N

Nate -

I don't know whether that Protege5e has a voltmeter on the dash (!), but I've "suggested" to him that he check the output voltage at the alternator/regulator!

Thanks all!

Reply to
n9ejs

I'd be more concerned that the voltage is fluctuating while he's driving... that's why I asked if there was one in the dash. That said, if it really were, it probably would have taken out something more expensive by now :/

nate

Reply to
Nate Nagel

That is a collossally stupid idea. He's already seriously reducing his seeing light with those dumb blue-tinted "extra white" bulbs; a resistor is only going to worsen the reduction in nighttime safety (his own and everyone else's). If he will simply start using the right bulbs instead of the wrong ones, the problem will likely go away.

Reply to
Daniel J. Stern

More to the point, if he did have transient voltage spikes, he'd likely be losing bulbs all over the car, not just in the headlamps. It's sounding more and more as if the owner's foolish bullheadedness in continuing to buy short-lived blue-glass "extra white" bulbs is the real problem here.

Reply to
Daniel J. Stern

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