Project 4Runner: When good LEDs go bad

Sometime ago I switched out the factory interior light bulbs of my 4Runner to LEDs. The LEDs were purchased from a forum recommend eBay seller, Fyre Flys. The idea was to have more light and less power draw. This was a win-win, as my daughter always puts he dome light on to read but frequently forgets to turn it off, draining the batter in process. 
The LEDs worked great when installed. The light was much whiter, little cold for some, and much brighter. 
Then, one day, the main dome-light stopped working. Ugh. I thought that perhaps the bulb assembly just slipped out of the socket as those looked sort of flimsy. Nope. It was busted. More importantly, when I tried to removed it, it was very hot to touch. 

See that blacken section of the LED bank on the right? That is a sign of what is known in the industry as a thermal event. The damn thing burned up. What has me really worried that the LED was hot to touch when I was removing it, many weeks since the last time it was illuminating. 
This means that the burnt LED was drawing current the whole time, or at least when the door was open or the dome-light switch in the on position. But instead turning that energy into light, it was turning it into heat and that is really worrisome. Basically, it did not fail safe. There was no open circuit upon LED failure but rather a closed circuit where the burned LED basically acted as a resistor.
Is this a poor design or poor quality components? I don’t know, perhaps both. Now I have to yank all those bulbs back out. 45 dollars wasted. 
I will call Fyre Flys and see what, if anything, they offer me. I contacted them regarding their eBay and website price discrepancy but never got a reply. 

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6 responses to “Project 4Runner: When good LEDs go bad”

  1. nanoop Avatar

    There should be some kind of current limiter (i.e. resistor), I wonder if that’s part of the assembly (so that one failed, probably the assembly bit since resistance is pretty elementary…) or expected to be an external element (i.e. not working as advertised). I don’t know how these are designed, though.
    Third possibility would be production fail, which I’ve seen a lot with cheap off-brand LED assemblies for household “bulbs”.
    Fourth would be using it out of specs.

  2. Batshitbox Avatar

    Two things about LEDs:
    They need to be properly heat-sunk or this happens. This is either poor design or it wasn’t intended to be put in an enclosure in that orientation. Dome light? Was the sun on the roof? Dome lights don’t have a 100% duty cycle, so your daughter running the dome light for 30 minutes could have exceeded the design parameters. (My brake lights used to stay on, and the incandescents melted the plastic around the bayonet sockets as a result.)
    “White” LEDs are basically a very light blue, especially the cheap, high K variety. Blue light scatters more readily, and so despite clams of candlepower, the light from them fails to carry very far. My eyes don’t detect the short wavelengths they operate on, and I can’t see as well under a car with an LED light as I can with an incandescent or fluorescent. This makes them a bad choice for interior lights for me.

  3. dukeisduke Avatar

    I previously bought some LEDs online (also eBay), but I’ve never been impressed with the quality. My ’95 F-150 used a 912 bulb (large diameter bayonet type) for the center high mounted stop lamp, and two 194s for the cargo lights. After more than ten years, the bulbs (I went through two or three) cooked the socket (made from silicone or a similar material), and warped the housing.
    I had to go to a junkyard to get a used complete lamp assembly, since the dealer wanted $200 for the assembly, and over $100 for the sub-harness with new sockets (WTH?). I then took one of the cargo lamp sockets from the junkyard part and spliced it in to be the new CHMSL socket. I ordered two two-packs of LED 194 replacements (no one had a 912 equivalent) from eBay, and replaced the 912 CHMSL, along with the cargo lights.
    The LED was never as bright as the 912, and projected a somewhat bright circle of light, instead of filling the entire red rectangle with bright light. Also, within a year, all the LEDs (surface mounts) on the bulb had died, except for the one on the end. Very disappointing.
    The big names, like Sylvania, have gotten into the game now, and are starting to offer LED bulbs. I recently bought a 2-pack or 168/194 bulbs, from the local outpost of the Irish-named auto parts chain. They weren’t cheap ($14.99 for the 2-pack), but I’m hoping they’ll outlast the eBay stuff. They look very different from what I’m used to seeing; they’re very compact, and look like a solid white plastic bead the size of an English pea, with the bayonet part (also white) attached. I’m planning to use them for license plate lights on the wife’s ’08 Sienna, since replacing them requires pulling off the liftgate trim panel (a bit of a pain, and I usually break at least one or two snap fasteners) and the pull-down strap.
    If I like them, I’ll buy more for the license plate lights on the Tacoma, and look for ones to replace the backup lights.

  4. Rust-MyEnemy Avatar

    When I worked in warranty I would deal with endless complaints about bulb failure warnings from people who had just bought a used car. Invariably it was where the sidelight or indicator bulbs had been swapped out for LED items by the previous owner – the bulbs are outside the electrical resistance / power consumption parameters the car is set up to recognise, so it assumes an open circuit.
    While I can understand the motivation for putting them in interior lights (though I despise the way they look) there is no justifiable case for retrofitting them in sidelights and indicators instead of the incandescent bulbs the factory fits – you’re only introducing a new failure point. People just can’t help but fiddle because “upgrade”.

  5. TobyShine Avatar

    E-bay crap! I’ve used many from have not had one fail. Pricier for sure but much better quality.

  6. Peter Tanshanomi Avatar

    “When CRAPPY E-BAY LEDs go bad.”
    Fixed it for you.