3rd Brake Light Q?

BlueOvalFitter

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Awhile back my son installed some LED bulbs in my 3rd brake light. I bought them from Amazon and they have a 1 year warranty.
The 2 outer lights are for lighting up the bed at night. One of the 2 goes out every now and then. Then, it works fine for awhile before it goes out again. I'm thinking the bulb might not be in the socket all the way? 🤷‍♂️
I know just enough about vehicle electrical systems to keep me out of trouble.
Does anyone here have ANY ideas what might be going on?
Thanks! :)
 
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[Quote:] "I know just enough about vehicle electrical systems to keep me out of trouble."

Since I know even less than you, I'll shoot from the hip here::D
If they're incandescent lights bulbs, the inside filament may be broken and only sometimes making contact.
Check the bulbs contact in the socket itself(as you mentioned) but most likely it is again breaking that contact and you'll need another bulb.
 
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BlueOvalFitter

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[Quote:] "I know just enough about vehicle electrical systems to keep me out of trouble."

Since I know even less than you, I'll shoot from the hip here::D
If they're incandescent lights bulbs, the inside filament may be broken and only sometimes making contact.
Check the bulbs contact in the socket itself(as you mentioned) but most likely it is again breaking that contact and you'll need another bulb.
I still have 5 left in the pack. Looks like my son will be fixing it for me this weekend.
 

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I am not sure if your son drive a "generic" car that is brandless but I would think that the car make model year may point to a better advise?
 

BlueOvalFitter

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I am not sure if your son drive a "generic" car that is brandless but I would think that the car make model year may point to a better advise?
Wait, what? My son drives an 04 (new style) F150 Lariat and an 96 Corolla. What "advice" are you saying he needs? :unsure:
 

AZjeff

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Can you give me an example of what a good LED bulb is?

No idea but the cheap 10 bulbs for $10 or whatever aren't. I tried some LEDs in those bed lights on my previous Chevy and they were noticeably dimmer than the stock bulbs. Tossed them. It seems reasonable to think a replacement LED should cost more than an incandescent.
 
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Unfortunately, the best 921 LED retrofit bulb, the Philips 12841B2, was discontinued a few years ago in favor of a cheaper new version.

It's difficult to replicate the output produced by a filament, and harnessed by a reflector, using a bunch of LED emitters.

The designs that are effective, albeit not universally -- it depends on the fixture design -- are like that Philips bulb. They utilize a few high-quality emitters that have their output directed at the reflector, which does the work, as with an old incandescent bulb. Not a bunch of cheap SMD emitters that rely on ambient radiation to illuminate, leaning heavily on quantity over quality.

The most common attempts, using a phalanx of emitters resembling a disco ball, attempt to overcome that through brute force, and don't work well the majority of the time. Those that are designed and made cheaply are even worse. More so when sold at marked up prices justified by hollow marketing. If one wants to experiment with them anyway, just order them from AliExpress at a much more realistic cost.

Also unfortunate is that the reputable brands, like Osram/Sylvania, and Philips have dialed down their efforts from before (that 921 is just one example), and moved away from the good designs in favor of cheaper, less effective ones.

And keep in mind that, while the crappy LED retrofits are mostly harmless when used for things like general/interior lighting, using them in functional and signalling applications -- brake, reverse, signals, etc. -- increases risk. It's clearly evident when stopped behind a vehicle with such retrofits, and all that emanates from the lights is a dim glow, and/or a rapid flash, which the owner/driver is oblivious to.

There are potential benefits with general applications -- a 3W LED in that bed light is going to drain the battery much more slowly than an 18W 921 -- but if there are no good solutions, sometimes it's best to stick to the tried-and-true that is known to work.
 
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The pictured pack of bulbs, hard to see exactly what they are through the bag but AFAICT, they look exactly like some packs of bulbs I have.

Instead of putting them in a vehicle, I've been using them for incan replacements for a landscape lighting set. They fail constantly, some of which start to flicker for a while, and other coming on, going off, for periods of time.

They break the bond wires inside the LED because they are being overdriven above 12.0V. I know, you'd think they would design to tolerate a vehicle electrical system where you're up closer to 14.(x)V with an alternator running but that's not the case, they fail with a few dozens of hours or less on them if much above 12.0V.

My solution for the landscape lights (which were originally 12VAC then I converted to DC but still floating closer to 14-15VDC) was put a buck switching regulator in series. That's a bit much for your application but a series resistor to reduce current should help, or of course just get better lights, but in my case I got a ton of them (10 boxes) so it was worthwhile to mod the supply rather than buy new bulbs then wonder if 14V-15V was too high for them too because this bulb form factor seldom has its own current limiting circuit integrated in, base of the bulb is a little too small for that.

It's hard to suggest a replacement, ultimately the best option for an integrated housing is to use an LED mounted on a "star" backplate, put on a sheet aluminum plate to heatsink. Anything bulb shaped that fits in a traditional socket is usually going to be dim (unless overdriven to short life) within the available space with that bulb form factor (T10 wedge aka 921).
 

BlueOvalFitter

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The pictured pack of bulbs, hard to see exactly what they are through the bag but AFAICT, they look exactly like some packs of bulbs I have.

Instead of putting them in a vehicle, I've been using them for incan replacements for a landscape lighting set. They fail constantly, some of which start to flicker for a while, and other coming on, going off, for periods of time.

They break the bond wires inside the LED because they are being overdriven above 12.0V. I know, you'd think they would design to tolerate a vehicle electrical system where you're up closer to 14.(x)V with an alternator running but that's not the case, they fail with a few dozens of hours or less on them if much above 12.0V.

My solution for the landscape lights (which were originally 12VAC then I converted to DC but still floating closer to 14-15VDC) was put a buck switching regulator in series. That's a bit much for your application but a series resistor to reduce current should help, or of course just get better lights, but in my case I got a ton of them (10 boxes) so it was worthwhile to mod the supply rather than buy new bulbs then wonder if 14V-15V was too high for them too because this bulb form factor seldom has its own current limiting circuit integrated in, base of the bulb is a little too small for that.

It's hard to suggest a replacement, ultimately the best option for an integrated housing is to use an LED mounted on a "star" backplate, put on a sheet aluminum plate to heatsink. Anything bulb shaped that fits in a traditional socket is usually going to be dim (unless overdriven to short life) within the available space with that bulb form factor (T10 wedge aka 921).
 

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^ Yes those look like mine, 6 x 5630 LEDs and the top half of the bulb is extruded aluminum, painted black, and after they overheat long enough the black turns more golden colored.

Forgot to mention that the electrical contacts are literally the leads from the two resistors inside so another option is bend them straight, pop the plastic base off, and swap in higher value resistors in to reduce current.

Unfortunately all my landscape lights use T10 except the floodlights are bi-pin. I put these in the floods and they were tolerant of the higher voltage due to a built-in current regulation stage:


If you were to hard wire (solder) to bulb leads, or were able to switch the bulb socket type, you could switch to a different bulb form factor that has built in current regulation.
 
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Looking again on a bigger monitor, your bulbs look very similar but not exactly the same, yours don't have an aluminum top cap on them while mine do, but it wouldn't surprise me if they suffer from the same issue of optimized for 12V, using two resistors in series and 2x parallel of 3 LEDs in series, so quite a large difference in drive current between 12.0V, and higher voltage when ran on a vehicle electrical system.
 
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