ok, i just finished installing window motors and white gauges,(man my hands and arms hurt) anyway, i dont like the way the gauges look now being back lit,what i want to do is front light them using 5mm red leds ,i would drill a hole in the top of the black trim piece for each gauge,i can find 5mm red leds on the web and even the holders for em, however id like to know how you would hook them up ......they have 2 prongs on them that look like you could solder them onto a circuit board or something, how would you hook em up to the cars wiring? and would a 12v system be too much for em? tia

 

i dont know how the stock bulbs get powered, but just find the positive and the negative from that. 12V is deffinetly too much and the led's will pop. Most leds operate at either 3.3V or 5V, you will need to get resistors [from radio shack or a place like it and ask them what resistors youd need to knock the voltage from 12v to either of the 2 mentioned, depending on the led]

 

the stock bulbs turn into a socket on the back of the gauge cluster,the current runs thru a surface mounted grid system i guess youd call it, how do you pull power off of that?

 

Notice on that "grid" how the "copper" or conducter surface is exposed at the light sockets and covered the rest of the way. The light sockets pull their power from that grid, 'cause the sockets have contacts on them that make contact w/ the grid. Your LED is polarity sensitive, you will have to have pos and neg hooked up properly. I guess you'll need a multimeter to read the voltage and see which side is neg and which side is pos on that grid. Good luck!

By the way, the old bulbs wont give you an indication... incandescent lights are not polarity sensitive.

I guess in worst case scenario (and depending on cost of material), you could order twice as many LEDs as you need, so that you can go thru the trial and error process. I would go ahead and order a few extra (if they're not too expensive) just to be on the safe side.

 

the leds are very cheap,i see what your saying, heres what im thinking i have to do and correct me if im wrong,i could solder two seperate wires onto that grid system and run them thru the socket where i just removed the stock bulb to the trim piece,hook up an led and see what happens when i turn on the juice, this leaves me with two more questions,if the led is hooked up backwards will it pop or not light? and what side would this resistor that dye spoke of go on ? positive is my guess?

 

Do a search for needle LEDs on here. Some guy had a post about wiring up LEDs to light the needles. He ran resistors inline to lower the voltage for each LED.

There is also a tech article that I hadn't noticed before.... https://www.thirdgen.org/newdesign/tech/leddash.shtml

 

i really appreciate that post ray, alot of usful info in that tech article, i was able to find the leds , wires and socket lenses on jameco, thanks for that as well.......im good with my hands but electronics really isnt my bag, so i must ask this........according to the formula in that article i need resistors with 585 ohms resistance..jameco has 2 that are close , one is 560 ohms and one is 680 ohms......my guess is go with the higher one? im not sure because my thinking is if too much resistance the led wont light or too little it will pop......how much leeway is there in ohms?


hehe maybe i should post this on an electronics board somewhere?

 

So are you saying that you cant use something like this?

This is what I am using for my dash lights only the blue ones.
Brian

 

yeah im not going to use the stock sockets, that would be backlit with just different bulbs, im going to front light them from the top of the black trim piece or the top of the clear piece not sure yet.....hence i need to run wires to a socket with an led in it.....that you have there is just a direct replacement it looks to me....i dont like the way they look back lit....i painted the needles red and they look good but i can still see the original gauge shining thru the white overlay because they are back lit.....

 

also, say you are using 12 v source, you can run 3 4 volt leds in series and they will work like normal. but the system voltage on a "12 volt " system is actually 13.5 volts when the alt. is charging.

good luck

 

correct, i used 13.5 volts, the leds i want to use are 1.8 volts,if you read the tech article above you will see the formula for calculating the resistance needed, its kinda like a math test hehehe

 

welp i talked to an electrician at work today, according to him he said use the 560 ohm resistors, the led will be a little brighter but may not last as long, he said 25 ohms isnt that much to worry about........so

 

oh my gosh. you may take 2 hours off of the 100,000 hour life.

good chance is you will never have to replace them, unless you have have wireing short of some sort, then they all go cabom and smoke.

thanks
anthony