resistor or electronic flasher with LED turn signals

ken garchow

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i am wondering when using LED turn signal bulbs what are the pros and cons of resistors vs electronic flasher

thanks
 

N8N

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Resistor causes heat & will also negate the power savings of using LEDs. But you may need to use them if your car uses current measurements for lamp outage indicators. I'm assuming that you are using the Philips bulbs; if not, that's what you should be using.
 

ken garchow

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thanks
yes i am trying a philips 3157 red in my 2006 super duty rest stop/turn. right now i have one in and am looking at it in different lighting conditions and angles day and night to see how it compares to the incandescent side. but hard to evaluate the turn signal as it is hyper fast. my truck has no bulb monitoring system so thats not an issue. there is an electronic flasher available for it.
i have read that the electronic flashers don't always do the job w/ leds. but think it would be nicer install than having resistors at bulb locations
 

Norm

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The majority of LED bulbs available on the market today will make your vehicle unroadworthy and unsafe.

Please see rule 11

Norm
 
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Hamilton Felix

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Check with Virgil. There are now a FEW Philips LED bulbs that are legal for stop/tail/marker/signal use, though not in all vehicles. I recently purchased a pair of 100% legal Philips LED replacements for the 921 bulbs in the reverse lights of a Corolla. The illegal LED bulbs still far outnumber the few legal Philips bulbs, but legal (depending on the vehicle) LED versions of 1157 and 3157 do exist. All I can say is Shop Carefully.
 

-Virgil-

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Put in whatever flasher (or get whatever body computer configuration) is used for trailer towing; that will restore the correct flash rate. A test lab is really the only way to get an accurate go/no-go test. If you are doing a purely visual evaluation, install one of the test bulbs (leave the stock bulb on the other side). Turn on the lamps with the truck out in bright daylight. Walk about 25 feet away from the truck and move in an arc (180°) from one side of the truck to the other, keeping both lamps in view to evaluate their relative visibility. Watch for how bright the lamps appear, the apparent size of the lit area, any "dropout" angles, any "flash" angles (extra bright light), shadows, etc. Then double your distance to the truck and walk back and forth again to compare the two sides. Once it's dark out, move the truck about 4 feet away from a wall or garage door, at 90° (not crooked), turn on the lamps, and look at the apparent brightness and size of the patch of light shining on the wall from the two lamps. A handheld light meter goes a long way here. If the light patch on the test bulb's side is dimmer and/or smaller, or there are dark streaks/shadows, or (in the daylight observation) if there are angles from which the test bulb is less visible than the filament bulb, the test bulb fails in that application. Of course, if you do see any shadows or bright spots or other artifacts, check to make sure the standard bulb doesn't have a comparable artifact on the other side. Also be sure to compare (day and night) the apparent bright/dim ratio. Often an LED retrofit will have insufficient difference between the bright (brake) and dim (tail) mode, which is very dangerous; it basically renders the lights useless for conveying the message they're supposed to convey.

None of this is sufficient to say for sure that the test bulb is good enough, but it's enough to reject the test bulb if it's bad enough.
 
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ken garchow

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virgil

thanks for the detailed instructions on evaluating the bulb in my truck
ill print them out and start making the tests

i noticed you didn't comment on the issue of violating a forum rule
can you please clarify to assist in my learning

thanks
 

Alaric Darconville

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i was under the impression that the bulbs i was trying were the first DOT approved LED's per the philips website
Except that the DOT doesn't approve anything. Philips is playing games with the regulations because they know those units have differing performance in differing fixtures, hence:
Philips
Philips Vision LED lights have been tested with luminaires for specific functions of certain car models, and for these tested luminaires, the beam pattern measured fulfills the requirements as stated in the SAE standards.

Ken Garchow
also on the recommendation of a well known automotive lighting consultant
If it's Daniel Stern, I recall in my middle distant memory that I'd shared with him my opinion that Philips was playing those same games, and that he had agreed.

So, it's not exactly YOU, it's Philips. Still, the walkaround test that Virgil provided is important.
 

ken garchow

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thanks guys, I'm just trying to optimize my trucks safety, function and aesthetics.
i have read a few times that the speed at which a LED lights up in a brake light can save 10 feet of stopping distance.
that sounded like a good way to reduce chances of being rear ended, is that an untested sales gimmick also?

and who is the governing body when it comes to legal lighting?
and who enforces the rules?

ill do the walk around test as described
 

Alaric Darconville

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thanks guys, I'm just trying to optimize my trucks safety, function and aesthetics.
i have read a few times that the speed at which a LED lights up in a brake light can save 10 feet of stopping distance.

Filament bulbs have a rise time, and that time increases based on the voltage applied to them; vehicles with long trailers (such as a 53' trailer on a semi, or a chain of shorter trailers) and long thin/aging wires will have problems with voltage, increasing a filament's rise time. An LED's rise time is way closer to instantaneous than a filament bulb could hope to be, even at lower voltages. On the surface, it seems like there's merit to the claims, but there's some research from last year that doesn't state uncategorically that the benefit is real. It's probably more real when it comes to semis with trailers, due to the longer rise time, but for passenger cars, maybe not. (See this recent DOT publication to learn more.)

and who is the governing body when it comes to legal lighting?
Defining the legal lighting in the U.S. is the NHTSA.

and who enforces the rules?
That depends on a few things. Technically, the NHTSA should have subjected Philips to more scrutiny and perhaps blocked the "introduction into interstate commerce" the product that would tend to "disable a regulated motor vehicle lamp", since the things don't produce 100% compliant results in every lamp they fit.

On the highway itself, it's at the State and political subdivision levels (Highway Patrol, Sheriff's Dept, City Police). The NHTSA and/or DOT and/or Federal Police aren't driving around looking for you.
 

ken garchow

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regarding LEDs, seems like every time i get the itch to try them turns out to be more hassle than its worth
the philips at least passed a crude "which looks better" test day and night, but didn't do as well under described test conditions, still has some shadows and not fill the light fixture as well, but does have a decent looking brightness of the brake light portion unlike many leds i have tried

the 180 walk around at 25 and 50 feet was about the same both sides but the led has some hot spots and drop outs

plus can't find a similar amber front, so the rise time difference between front and rear bothered me

may try again if philips comes out with amber 3157's
 

jzchen

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In some late 80s to early 90s Mercedes some bright fellows were able to keep the hyper flash warning when a LED replacement bulb burned out/failed, more specifically removed as a test condition...

I take quite a bit of time finding this post to share with those swapping to LED bulbs. (Of course I try to express concern that LEDs do not quite fit the bill as a direct swap in, as of yet, but people will continue). Could the test directions here be stickied for ease of reference? Thanks!
 
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-Virgil-

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I take quite a bit of time finding this post to share with those swapping to LED bulbs. (Of course I try to express concern that LEDs do not quite fit the bill as a direct swap in, as of yet, but people will continue). Could the test directions here be stickied for ease of reference? Thanks!

Done. New sticky-thread created.
 

DenCon

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My preference goes with relay when possible. Many modern vehicles use proprietary relays that cannot simply be replaced or upgraded - those days are gone.
 
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