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Discussion Starter · #1 ·
Inspired by forum members Teksavy and Milivolt I did LED brake light upgrade mentioned here:
http://gm-volt.com/forum/showthread.php?205018-LED-quot-bulb-quot-upgrade...-hit-some-roadblocks

Obviously LEDs have many benefits—I upgraded all of a home lighting to LED bulbs a few years ago—but I was curious to explore the potential safety benefits of having instant on brake lights with virtually no latency or lumen ramp-up.

I came across this interesting research paper entitled "LED Stop Lamps Help Reduce the Number and Severity of Automobile Accidents".

Before I swapped out both bulbs, I did a 240fps comparison shot on iPhone: [video]https://vimeo.com/155768252[/video]
Interestingly the standard, OEM CHMSL (Center High Mounted Stop Light) appears to come on and go off before the upgraded LED brake light. Perhaps the incandesent brake light wiring is introducing a tiny bit of latency compared to the CHMSL wiring which is LED from the factory?

Thanks again to Teksavy and Milivolt for the inspiration and detailed write ups!
 

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Which bulbs did you use? They seems quite a bit brighter than the OEM bulbs. I did this same upgrade but used the Phillips led bulbs and they don't seem much brighter at all.
 

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Nice video!
So, these bulbs are plug and play? How did you get the old ones out?
 

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Ha, the video made me laugh! In the background you had someone creeping by, in slo-mo, just made me laugh for some reason. Anyhow, that was interesting how much faster the LED brake light was than the OEM one, but even more interesting was how fast the high center brake light was than even the LED. Would also be nice to see it live, and not slowed down.
 

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Although I'm not certain, I think the CHML is usually operated by a different/separate switch, for safety/redundancy reasons.
If that switch was adjusted to physically actuate earlier than the main brake-light switch, it would simply get current first.
 

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Interestingly the standard, OEM CHMSL (Center High Mounted Stop Light) appears to come on and go off before the upgraded LED brake light. Perhaps the incandesent brake light wiring is introducing a tiny bit of latency compared to the CHMSL wiring which is LED from the factory?
Or it could just be the LEDs. Some of them have additional circuity like capacitors to smooth out the incoming power, which can cause delays like you have. I've seen it with some LED traffic lights where I can see the fraction of a second delay between two different brands of light illuminating.
 

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It is very hard using normal cameras to tell the real brightness of the lights, as the cameras are somewhat more sensitive to infra-red (Just try pointing it at an IR remote while operating it). Do they look close to the same brightness with the eye?
 

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Although I'm not certain, I think the CHML is usually operated by a different/separate switch, for safety/redundancy reasons.
If that switch was adjusted to physically actuate earlier than the main brake-light switch, it would simply get current first.
CHMSLs are definitely operated by a separate switch, as you said, for redundancy purposes.
Think about how many vehicles you have seen where the CHMSL is the only stop lamp working.

The CHMSL is designed to be an LED, the car provides a lot fewer amps to the CHMSL than it does to the stop lights that are designed to be incandescent.
The aftermarket replacement is replacing a bulb. In order to not cause a bulb-out error, the LED unit has to provide a certain amount of resistance and soak up a certain amount of power. It would not surprise me at all if that resistance causes a fractional delay.
 

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I've seen it with some LED traffic lights where I can see the fraction of a second delay between two different brands of light illuminating.
Probably lights that has LED "bulbs" swapped out into a former incandescent unit, vs newer ones that are designed to be LED from the go.
Also, many retrofitted traffic lights has the red and green swapped out, but the yellow is still incandescent (the low total burn time of yellows makes them uneconomical to swap out). So the LED green goes off and there's slight delay while the incandescent yellow heats up.

Newer retrofit reds and greens used in cold climates now have a resistor in them that turns power into heat, because the first LED retrofits would get covered with blowing snow. The LED units did not make enough heat to clear the lenses like the incandescent did. The resistor can cause a delay, as shown on the Volt video.
New LED-built lights have a temp sensor and a heating element to clear the lenses.
 

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Which seems to explain why GM used incandescent bulbs back there in the first place!
 

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Discussion Starter · #14 ·
Like others, I too, used the Philips 7443 Red Vision LED Stop/Tail light (Pack of 2)
In person, the color difference is more apparent than the brightness—the philips bulbs are red LED's, compared to clear bulbs under a red lens.

As for the installation, Milivolt, posted some good instructions here:
http://gm-volt.com/forum/showthread......-hit-some-roadblocks&p=2988297#post2988297

These are the other bulbs I used:
License Plate: Philips 127916000KB2 194 Bright White Interior Vision LED light, 2 Pack
Rear Hatch: SYLVANIA 168/194/2825 LED Premium White Miniature Bulb, (Pack of 1)
 

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Is it better to use red LEDs or clear LEDs for the brake lights?
Red.

I just bought a pair of Philips 7443s today. Going to install them over the weekend.
 
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