The Truth About Cars » filament http://www.thetruthaboutcars.com The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. Tue, 30 Jun 2015 22:06:33 +0000 en-US hourly 1 http://wordpress.org/?v=4.2.2 The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars no The Truth About Cars editors@ttac.com editors@ttac.com (The Truth About Cars) 2006-2009 The Truth About Cars The Truth About Cars » filament http://www.thetruthaboutcars.com/wp-content/themes/ttac-theme/images/logo.gif http://www.thetruthaboutcars.com Piston Slap: Occam’s Razor Cuts Hardbody Headlight Headaches? http://www.thetruthaboutcars.com/2015/05/piston-slap-occams-razor-cuts-hardbody-headlight-headaches/ http://www.thetruthaboutcars.com/2015/05/piston-slap-occams-razor-cuts-hardbody-headlight-headaches/#comments Mon, 18 May 2015 13:00:28 +0000 http://www.thetruthaboutcars.com/?p=1069498   Robin writes: Hi Sajeev, It’s me again, steady reader, random poster/questioner, with another D21 question. My good old ’94 Nissan D21 is soldiering on, 213,000 and steady on. Of course I don’t ever thrash it which I’m sure makes a difference. But to get to the point: the other day I went out to […]

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My bad. (photo courtesy: imgflip.com)

Robin writes:

Hi Sajeev,

It’s me again, steady reader, random poster/questioner, with another D21 question. My good old ’94 Nissan D21 is soldiering on, 213,000 and steady on. Of course I don’t ever thrash it which I’m sure makes a difference.

But to get to the point: the other day I went out to go to work and presto! No low beams. High beams, check. All signals, markers and brake lights, check. Just no low beams.

Forum surfing ensued, all seemed to point to the switch stalk. I checked fuses. No headlamp fuse? WTF!

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What the… (photo courtesy: OP)

I’m hoping against hope that it’s something simple and stupid that I’ve overlooked in my attempts to shoot the trouble. And that another Piston Slap reader has a tip.

Because Piston Slap is only run twice a week, Robin beats us to the punch:

Hi Sajeev,

I emailed you not too long ago about my D21’s low beams going out all at one time. Replaced the switch stalk (a common culprit per several forum threads I browsed), scratched my head furiously over the fuse panel, girded my loins for the big $ hit of having someone with a clue troubleshoot the electrics. In the meanwhile, I drove around with my high beams on, undoubtedly pissing off my fellow North Texans.

So this morning I decided to just replace both sealed beams. At worst I’d still be in the same boat but new bulbs. Voila! It was the ultra-rare concurrent low beams burnout phenomenon.

Old Bill from Occam really knew his stuff.

Sajeev answers:

I’m glad to hear you fixed it. Perhaps you also needed that new headlight switch, as it sounds like a multifunctioning switch which are known to misbehave in the oddest ways after 10+ years. Anyone with even a passing interest in Nissan Hardbodies should download this PDF. Yes, it’s for a 1990, but it’s a start.

I looked at page EL-41 and saw nothing fishy about Hardbody headlights: fuses, connectors, grounds, etc as expected. I am stumped as to why your 1994 fuse box doesn’t list a fuse a la the 1990 shop manual. While I think Occam’s Razor applies to the 15A fuses (if you have them!), having both headlights blow out simultaneously is odd but the obvious problem after that. Why?

Bonus! A Piston Slap Nugget of Wisdom: 

Because headlights are a wear item. I’ve said this multiple times before, if your halogen bulbs are 5+ years old and the filament’s shiny finish isn’t chrome-like (it’s tungsten, but you catch my drift) in perfection, they probably need replacement. Hell, I’ve seen a certified pre-owned, two-year-old used car (presumably with thousands of night miles under its belt) need new bulbs so the new owner can see safely at night.

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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Piston Slap: Reading the Light Bulb Filaments http://www.thetruthaboutcars.com/2013/01/piston-slap-reading-the-light-bulb-filaments/ http://www.thetruthaboutcars.com/2013/01/piston-slap-reading-the-light-bulb-filaments/#comments Wed, 30 Jan 2013 12:01:14 +0000 http://www.thetruthaboutcars.com/?p=475461 TTAC commentator Celebrity208 writes: Sajeev: I’d always thought that police crash investigators would check the tail light bulbs of a car that was rear ended to determine if its lights were on at the time of the crash. I thought it had something to do with the way the filament was broken/burnt/etc. So my question […]

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TTAC commentator Celebrity208 writes:

Sajeev:
I’d always thought that police crash investigators would check the tail light bulbs of a car that was rear ended to determine if its lights were on at the time of the crash. I thought it had something to do with the way the filament was broken/burnt/etc. So my question is two-fold, am I crazy and do they do this, and if so how might LED tail lights remove this piece of forensic evidence regarding correctly operating brake lights at the time of an accident (presuming the fault was contested)?

Sajeev answers:

Hi Clayton! You are not crazy (I hope) but I doubt the Police check the tail lights/brake lights in some sort of CSI operation for car accidents. For two reasons:

  1. The wear from cold or hot “restrikes” of a tail light bulb’s filaments probably don’t tell much, other than their remaining lifespan. And once the vehicle crashes, well the evidence could be destroyed. Headlights, however, are a different story.
  2. Why bother with this when we have event data recorders?

Here’s a list (unverified for accuracy) of late-model vehicles with EDRs.  Basically any vehicle with an OBD-II computer (1996-present) is capable of recording a metric ton of data as to your driving habits.  Combine this 1990s advancement with the ancient technology of the brake light switch and you’ll know exactly what was going on before the accident.  Why bother looking downstream (light at the back of the car) when you see the source upstream (at the brake pedal assembly)?

Bonus! A Piston Slap Nugget of Wisdom:

This talk of lighting filaments always takes me back to a core truth of automobile ownership: check the filaments on your (Halogen) headlights!

If the chrome plated(?) looking finish on those tiny wires isn’t flawless, replace the bulbs. In pairs!  Life is too short to risk it all on $20-30 worth of new bulbs, as they degradate so slowly that a visual inspection of the chrome plating is the cheapest and easiest way to ensure your nighttime driving safety.  I’ve seen 2-year-old vehicles in dire need for new bulbs!  So it happens, and you better do something about it.

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry.

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