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Old 06-07-2013, 10:24 PM
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LED dash light question

Ive already put the 194 LED bulbs in, and the 37 LED's came today. I know theres a positive and negative on these bulbs and the slots you put them in, but how do you tell? The illumination bulbs were easy because you can see them light up when you plug them in, but the others seem like aux lights, turns, ect. So with those they wont be lit all the time.

How did you guys do it?
 
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Old 06-08-2013, 12:12 AM
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I'm not sure in your case, but...
LEDs are identified by the negative pole (lead) being the short, by a flat spot (or notch) on the rim of the LED next to the negative, or by having the round solder pad.
If you can see the internal parts, the largest one of the two is usually negative. LEDs are polarity sensitive, so i would expect something on the light to indicate polarity.
 
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Old 06-08-2013, 12:37 AM
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You can touch leads to a 9 v battery if it lights up then you have it right if not swap leads around then mark neg with a marker to keep it a easy install
 
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Old 06-08-2013, 07:55 AM
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Originally Posted by Diablo540
You can touch leads to a 9 v battery if it lights up then you have it right if not swap leads around then mark neg with a marker to keep it a easy install
Only if the light is rated for 9-12V. Otherwise, it will immediately burn out the light.
Lights to be specifically used for the instrument panel should be 12V compatible. They have a resistor built in.
 
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Old 06-08-2013, 08:04 AM
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Ok it looks like eveyone of the LED's has a little notch in it, so that should be negative. Now for the black piece you plug them into, is there anything on those?
 
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Old 06-08-2013, 08:14 AM
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Originally Posted by pin8246
Ok it looks like eveyone of the LED's has a little notch in it, so that should be negative. Now for the black piece you plug them into, is there anything on those?
You have bare LEDs? What forward voltage are they rated for? If not rated for 12V forward voltage, then you need a resistor that is appropriately sized on the positive lead.
The LEDs should be packaged already, and ready to put in their place.
If you have bare LEDs, you also need resistors or they will burn out immediately when you energize them.
As far as the holders go, there is no marking because the holders are not polarity sensitive. The only thing that matters is to get the LEDs correctly lined up to the polarity.
 
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Old 06-08-2013, 08:23 AM
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Looked at the ebay page I bought them from and there sayin DC12V so I should be good without the resistor. And what are bare LED? They look like the 194 ones I bought that work fine, just dont know what bare means.

And what do you mean to get them lined up to polarity? Figured they would have to go in the clip a certain way since they have a negative?

Im new to this so sorry for the stupid questions.
 
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Old 06-08-2013, 08:57 AM
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Originally Posted by pin8246
Looked at the ebay page I bought them from and there sayin DC12V so I should be good without the resistor. And what are bare LED? They look like the 194 ones I bought that work fine, just dont know what bare means.

And what do you mean to get them lined up to polarity? Figured they would have to go in the clip a certain way since they have a negative?

Im new to this so sorry for the stupid questions.
I believe that the only stupid questions are the ones that don't get asked. You cannot do anything without information, and someone else might have the information you need. The only way to get it is to ask.

DC12V from the website means you should be OK to put them in the instrument panel without a resistor.
Bare LEDs are just the bulb without any mounting or other attachments (just the bulb and two leads). That is how I buy them for other projects.

Lined up to polarity means to attach the positive lead to positive power, with negative lead to negative power (or ground). The dash has contacts for each on the plastic film on the back of the instrument panel, you just have to get them in correct or they don't work. No damage to the bulb, they just don't work.
The clip doesn't have polarity, the bulb does. Shouldn't matter which way you put the LEDs in the mount, but will make a difference which way you put the mount into the holes in the rear of the instrument panel cluster.

Can you post a link to the ebay page? I might be able to help you easier if I know what you purchased.
 
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Old 06-08-2013, 09:03 AM
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10x Flat Ultra White 6000K 37 58 70 73 74 T5 1 LED Wedge Bulb Dashboard Gauge | eBay

See if that works. You should be talking about the metal connectors on the outsides of the clips. Now where those twist in, what side is the negative. If I recall right, on the back side of the dash where it says what the bulbs are for I dont see anywhere where it states or show negitive on it. I could be wrong since im just asking questions now before I go pull apart again.
 
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Old 06-08-2013, 09:23 AM
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Originally Posted by pin8246
10x Flat Ultra White 6000K 37 58 70 73 74 T5 1 LED Wedge Bulb Dashboard Gauge | eBay

See if that works. You should be talking about the metal connectors on the outsides of the clips. Now where those twist in, what side is the negative. If I recall right, on the back side of the dash where it says what the bulbs are for I dont see anywhere where it states or show negitive on it. I could be wrong since im just asking questions now before I go pull apart again.
Helps a huge amount. Those are packaged LEDs, resistors included.

On the back of the instrument panel there is a thin plastic sheet that has metal paths on it. The metal paths are called traces and function as a wire.
Around each hole, there should be bright parts of the traces exposed (the connection pads). There should be two of the connection pads per hole. Pick a hole and look carefully for one of the two connection pads to be connected to another connection pad at a different hole. That would be the negative side for both holes.
The positive connection pads will not connect to other connection pads.
Connect the negative of the LED lights to the negative connection pad when the mounts are inserted.
 
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Old 06-08-2013, 09:55 AM
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Originally Posted by srteach
Helps a huge amount. Those are packaged LEDs, resistors included.

On the back of the instrument panel there is a thin plastic sheet that has metal paths on it. The metal paths are called traces and function as a wire.
Around each hole, there should be bright parts of the traces exposed (the connection pads). There should be two of the connection pads per hole. Pick a hole and look carefully for one of the two connection pads to be connected to another connection pad at a different hole. That would be the negative side for both holes.
The positive connection pads will not connect to other connection pads.
Connect the negative of the LED lights to the negative connection pad when the mounts are inserted.
That was explained very good.
 
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Old 06-08-2013, 10:01 AM
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Originally Posted by BasicBajaX
That was explained very good.
Thank you. I try for clarity. Makes ideas easier to understand.
 
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Old 06-08-2013, 11:33 AM
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Thanks srteach. Just put them in, but being horrible at wiring following the negative side proved to be harder than I thought. So got them all put in, then resorted to the flicking the key on and off method to make sure they all were lighting up. Done though.

I noticed with these as opposed to the normal light, you seem to see the ABS, air bag light, ect more even if there not lit up. I may be over thinking it but it still all works. Also in between 70-80 mph still is a little more dim than the rest, but not as bad anymore.

Thanks for the help.
 
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Old 06-08-2013, 02:23 PM
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You're welcome
 
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