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Discussion Starter #1
bought some cargo light 25 smd LEDs. installed them and there bright as hell.......after a few times of turning them on only the very end one comes on on both of them. if i install the factory bulb they they will work again for awhile....what gives?
 

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Fortunato
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LED's are wierd sometimes, did you try to turn the bulb around. sometimes thats works.
 

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NBS right? You bought 921 bulbs?

How many bulbs are in the 3rd brake housing? 2 red and 2 clear? It's been a while since I've replaced mine.

And when you say you put the factory bulb in and the LEDs work for a bit, do you mean you have one filament bulb and one LED one next to each other and when you have them set up like that all the LEDs light up, but when you have both LED bulbs they only work for a little while then most of the LEDs shut off?
 

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Discussion Starter #5
NBS right? You bought 921 bulbs?

How many bulbs are in the 3rd brake housing? 2 red and 2 clear? It's been a while since I've replaced mine.

And when you say you put the factory bulb in and the LEDs work for a bit, do you mean you have one filament bulb and one LED one next to each other and when you have them set up like that all the LEDs light up, but when you have both LED bulbs they only work for a little while then most of the LEDs shut off?
Correct ill put one filament bulb back in and the other LED will work so ill put LED in both they work for awhile then most will quit
 

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What I would do, just for the sake of chasing down possibilities, is check the voltage readings at the third brake light. Put one filament bulb in and check the socket next to it, then put one LED in and check the voltage again.

And if the voltmeter has an ohm setting, you can check the LED bulbs and see if maybe that's where the problem lies.
 

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Discussion Starter #11
alright ill give that a shot later (raining now)
and yes it also has a ohm setting but never used it before
 

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Discussion Starter #12
not really sure what i was doing but this is what i came up wit.....

with just the tip LED working it showed up at 5. something
with one LED light and put in the filament bulb installed it showed up 16 something and the LED started working
installed the other LED and it showed up at 16 something....

now what lol
 

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is Bi-Winning and a
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Weird. I want to get some LED bulbs for my cargo/third brake light....now you got me second guessing it. lol
 

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2wd-RazorbackChevy
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bought some cargo light 25 smd LEDs. installed them and there bright as hell.......after a few times of turning them on only the very end one comes on on both of them. if i install the factory bulb they they will work again for awhile....what gives?
just invest in the cargo lamp I have. I'm on the phone right now so I can't post pics. it's 6 bright red led's for the brake and 12 (6 on each end) bright hyper white led's for the cargo. I got it off eBay for like 50 shipped and it's been on like 2 years now and hasn't failed once. I say get one :thumbsup:
 

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Discussion Starter #15
might have to check that out.....


but i want to figure out why the hell mines not working first!! lol

i havent found anywhere where anyone else is having this problem is the weird thing
 

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Discussion Starter #19
no shit.... i wonder if it has something to do with having so many smds on them?

:think:
 

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whats the deal with the Ohms that im suppose to check?
You set the multimeter to the diode setting (should look like an arrow) and check for a reading. What that reading is isn't as important as long as there is some value one way and none the other. The way that should have current going through it is when you attach the negative terminal of the multimeter to the cathode (- side of the LED) and the positive to the anode (+ side of the LED).

This isn't easy to know which is the anode and which the cathode, since on an LED bulb there should be 4 contacts, but it's typically the contacts across from each other, so if you turn the bulb with the tip facing down and the wedge facing up, you want to touch bottom left and top right contacts. Then just switch the terminals of the multimeter around and one way should show some voltage and the other shouldn't.

To be honest though, this is a real mystery to me. I'd like to bench test it with 12V and see if it stays lit up. Could be defective bulbs, but given that they stay on and work for some time, then just some of the LEDs stop has me scratching my head.
 
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