LED taillights not working

[PA Firefighter]

I have had these particular 7443 LED tallight bulbs for just over a year. Last night, I noticed they wont come on with the headlights. They still function 100% when braking. I tried taking them out and putting them back in to ensure a snug connection: fail. Any suggestions?

[AlaricD]

Replace the LED bulb with a 7443.

LED bulbs do not function properly in a reflector assembly designed around a filament bulb.

[fishexpo101]

Verify that you have power running to the connector - swap it with a filament bulb and see if it works. If the socket is fine, chances are the load resistor on the LED assemble is toast.

Assuming that you mean they don't light up when you turn on the headlights. If you mean the DRL function - the rear lamps don't light up at all unless you hit the brakes. May also be a problem with the twilight sentinel sensor and associated circuits. Every once and a while - my Matrix will fire up the headlamps but the rear lamps are off, stepping on the brakes lights them up fine.

[PA Firefighter]

LED bulbs do not function properly in a reflector assembly designed around a filament bulb.

That's not the issue. I've had these LEDs in for over a year. These LEDs do not just fire in one direction, they fire in 9. it's shaped sort of like an octagon with 43 independent leds on the bulb.

Assuming that you mean they don't light up when you turn on the headlights...the rear lamps don't light up at all unless you hit the brakes.

That was exactly my problem. I got it sorted out. The LEDs contact pins must have gotten bumped somehow, because when the headlights were on without the brake being depressed, the third taillight would come on, there must have been some kind of crossing of the contact points when it didn't recognize the headlights being on. I took the bulbs out again, and put them in at a slight angle so the contact pins would catch all 4 points, and they lit up and stay lit then slid the bulb in the rest of the way. Very strange that it hasn't ever happened before, or since.

[AlaricD]

Originally Posted by PA Firefighter

That's not the issue. I've had these LEDs in for over a year. These LEDs do not just fire in one direction, they fire in 9. it's shaped sort of like an octagon with 43 independent leds on the bulb.

It's still the issue. The taillights go out of compliance with FMVSS 108, because the LED bulb is not a filament bulb. The reflector is designed for a point source lambertian emitter, not a barrel of 43 LEDs.

To quote Daniel Stern, of danielsternlighting.com:

The optics of a bulb-type lamp are designed to collect and distribute
the light from a single light source of very specific size, shape,
placement, and orientation. Anything other than that single light
source in that exact size, shape, placement, and orientation causes the
lamp not to produce the intended beam pattern. Period. End of
discussion. But nothing. LED lamps are great -- IF and ONLY IF they are
engineered from the start as LED lamps. I have tested just about every
"LED bulb" out there. The barrel-shaped ones, the cylinder-shaped ones,
the "spider" ones, the wafer ones, the disc ones...you name it, I've
seen it and tested it, and in EACH AND EVERY case the photometry and
light distribution are way, way off from where they need to be. Grossly
insufficient light, improperly distributed, grossly insufficient EPLLA
(effective projected luminous lens area -- i.e., size of effective
illumination). Improper bright/dim ratio. And this doesn't even get into
the thermal issues that require extensive engineering in LED lamp
assemblies and are wholly unaddressed with "LED bulbs". These "LED
bulbs" DO NOT WORK, full stop. The problem is not with the
implementation. The problem is with the concept. This is not something
you can look at with your eyes and say "Yep, the performance is good"
(or "adequate" or "acceptable") without extensive training, and even
those of us with that training -- especially those of us with that
training -- know subjective naked-eye judgements are useless for
evaluating the safety performance of automotive lighting devices.
Photographs, likewise, are useless. This will remain factual no matter
how fervently you want to believe "LED bulbs" work safely or
effectively. They just plain don't. Your vehicle's lights are not toys
for you to play with because you think LEDs are keen. They are safety
devices other drivers rely on to work safely and correctly (objectively
-- not just according to your guesses).

[PA Firefighter]

LMFAO! I'm not questioning whether or not the housing is DESIGNED for LED application. You completely missed the entire point of the post which was questioning WHY my leds were not TURNING ON, (i.e. something wrong with connection), not WHY I couldn't get sufficient light output or if I had compliance issues.

My car has not failed an inspection due to poor light output or distribution, and if I'm not mistaken, PA has the second most intensive inspection you can get. So there's his "other then naked eye" evaluation for you. The mechanics use a tool to determine how much light comes out of the reflector, and if it's too low, the bulbs get replaced. Guess what? Mine haven't.

[AlaricD]

Originally Posted by PA Firefighter

LMFAO! I'm not questioning whether or not the housing is DESIGNED for LED application. You completely missed the entire point of the post which was questioning WHY my leds were not TURNING ON, (i.e. something wrong with connection), not WHY I couldn't get sufficient light output or if I had compliance issues.

[/quote]

Maybe so, but it doesn't change the fact that you're breaking the law and admitting as much publicly, and you're putting public safety at risk.

My car has not failed an inspection due to poor light output or distribution, and if I'm not mistaken, PA has the second most intensive inspection you can get. So there's his "other then naked eye" evaluation for you. The mechanics use a tool to determine how much light comes out of the reflector, and if it's too low, the bulbs get replaced. Guess what? Mine haven't.

It may be the "second most intensive inspection you can get", but that silly test isn't even close to the rigorous testing required under FMVSS 108, which defines not only minima, but maxima, and at what angles those minima and maxima occur. I don't think the grease monkey at Fred's Auto Service has access to a decent photogoniometer, nor would he know how to use it.