Acuracy02

Alright, so here's the deal: I am planning to convert my guages to be LED lit rather than the factory incandescent bulbs. I have purchased enough 5mm LED's to do the project (2 for each socket as advised by UglyPsycho) and have done extensive research on this site (including Nate's write-up, I actually emailed him about something already). I understand how to wire up the LED's and resistors if I am doing so on the rest of the dash which have sockets with no back because the LED and resistor have plenty of room. But I am not doing the rest of the dash, only the guages and this is what the sockets on the guage cluster look like:



Question is...how do I wire a resistor for each LED into the socket, fitting two LED's in each socket and having enough room for the resistors?

LED's ordered were the shaved version of these: LINK

Another pic of the cluster just for reference:

PenancE

hmmmm ur ur own leds onto the guage itself? cuz ledautomotive gives ur the wegde leds, all u gotta do it take out the old, put in th enew, i soldered the dash on my car wit resistors, and yea can be a little bitch, but how can u do it wit that type of socket? the dash has the flat back, but the back on the guage r covered, so i dont really know how u can solder that one...

PenancE

two leds in 1 socket? wtf?

demolition_x

how big are the wedge bulbs in the back? i don't think you need resisters since they are not blinking.

theshrink

haha... that's funny... no... the resistors drop the current... and what i would do ... is just put two leds in a series and then a resistor... and try to keep the leads as long as possible and put them through where the bulb had the leads originally... if that makes sense?

Acuracy02

2 in one socket bent away from each other works better to illuminate without patchy lighting and since the LED's require much less power it isn't a power issue.


Resistors are necessary to A.) tone down the brightness of the bulb (I will be using 680ohm resistors) and B.) protect against the bulb frying if installed backwards, etc.

theshrink

no... resistors drop the current... they will not tone down the brightness of the bulb, they will actually allow the leds to receive the correct current/voltage allowing it to light up as bright as it should for it to not burn out... and it will not protect it from frying if it's installed backward... i'm not sure where you got that idea from but a resistor has nothing to do with that kind of protection... i think that you may be talking about a diode, a diode directs a current and would stop it from going in a certain direction.

demolition_x

well do you think just 2 leds are going to be bright enough. the ones they sell are 5 leds per a bulb.


the reason i ask is that i just bought 6 led bulbs.

and i was wondering if these would fit back there?

theshrink

notice that one of the leds he bought... is about as bright as that whole thing... so it'd be brighter...

theshrink

and if i were you ... i'd look into using something around 390 ohms... and if you could fit it... try using 1/2 resistors

demolition_x

these look like they would be great for this. but they look like they might be a little too long




i would imagine they would eliminate hot spots

Acuracy02

I'm not sure you are following what I am doing. I am not using any "bulb" that has a socket. I am going to be hardwiring in bare LEDs. They look like this (as I showed in the link I posted):




except mine will be shaved for a wider angle

demolition_x

i know what your doing. im just asking since i rather not solder any thing permanent, if these bulbs would work that would be great.

theshrink

ahh... now that i took a closer look... i take that back... hmmmm... what i would do ... is just wire two leds in a series... with a resistor rated at least 390ohms... nothing less but something really close... preferably a 1/2 watt resistor ... and somehow try to solder that bunch to the leads on that socket ... if that makes sense... that would be the easiest... or just solder right onto the board... but i like to do things that are easier to reverse... ...oooooooor do what i did... go to superbrightleds.com buy the cheapest bulbs for the 192 size... rip out the leds... and once you solder all the stuff together put the wires from your bunch into the base of the led bulb...

Acuracy02

I believe the size of the bulbs that go in the blue base (not the red base, those seem significantly smaller) are size 74.

demolition_x

which ones do you need then?

what are the different bases for?

Acuracy02

Red Bases = Odometer Screen Lighting
Blue Bases = Guage Lighting





Still searching for the answer I need....

t0ast

I would suggest you ditch the socket all together. Wire each LED with a resistor and then solder the leads to the LED to the cluster. Just make sure any exposed leads in the hole are covered with shrink wrap/electrical tape/hot glue. Depending on how deep the holes are in the cluster, you may be able to have the resistor in the hole. Just make sure that after you solder them in, cover the hole with tape so you don't lose any light coming out of the back of the hole.

The other option if the fit is really tight is to run extra wires. Run a wire from the + in the instrument cluster to somewhere remote where the resistors are located, and then run another wire back to the + of the LED, which is soldered to the - in the cluster. That would solve your resistor location problem, but it just takes more work and there would be extra wires. Plus you'd have to leave the holes exposed and cover them with tape again.

Also when you're aiming the shaved LEDs, try to look into the hole. There's usually a flat facet to the plastic in there that spreads the light evenly through the cluster so aim the LED towards that.

If you want, I can try to take some pics cuz I'm probably gonna continue doing an LED conversion on my friends car tommorrow.

Acuracy02

Thanks a lot. I know what you are saying in both scenarios and will probably just hardwire in the LEDs as you suggested in the first part of your reply. The problem here is I have to know what side of the hole is positive and which is negative. I know the longer prong off the LED is positive, but if I hardwire in the LEDs and they are backwards then I have a major issue....

Pics would be amazingly helpful. Thanks t0ast.

theshrink

wow i'm sorry but are my posts invisible? well good luck... i have all the info you could possibly need... but guess you don't want it. Also i'm not sure how resistor size could be a problem when there are resistors that are 3mm wide and about 5mm long? I've redone many dashes completely.

t0ast

Figuring out the +/- is pretty much hit or miss. I know in a nissan cluster (1998 made in Japan), it says +/- where the harness goes into the cluster. From there, you just follow circuit board as best as you can to guess which lead is which at the bulb connection. However, in the toyota cluster (2002), there's no indication at all, and the circuit board is two-sided so its hard to follow. What I had to do was just solder the LED with resistor, plug it in, turn it on, and check that all the LEDs come on. Yeah, its a pain to guess and check, but as long as you have the proper resistor wired in series with the LED, it won't fry the LED nor will it fry the cluster.

Acuracy02

So all that I would be doing is soldering the + and - leads from each led to the contact point the original socket twisted on to, placing a resistor on the + lead prior to where to contacts the circuit board? If that is the case I understand what you mean t0ast. My LEDs will be here next week I believe so I'll wait for your pics and do some more research on my options. Yours seems to be the best bet. My concern is finding room for the resistor but hopefully your pics will clear that up too. Thanks.

PenancE

just buy the wedge leds from ledautomotive.com

Acuracy02

That was my first option but I quickly realized it is no where near as bright as an LED dash should be. So I'm attempting to follow in UglyPsycho's footsteps and do the 2 LED in one socket deal.

t0ast

Sorry these aren't the greatest pics cuz of the sizing, and I was doing the LEDs in the AC unit rather than the speedo, but I hope they help.

First pic: here's an LED halfway wired into one of those bulb holders. I just stuck the LED leads into the center holes. I took one lead and bent it into the existing contacts - the "J" shiney shape. The lead that's sticking straight up was used to solder the resistor (See next pics). After soldering that LED lead to a resistor lead, I bend the other resistor lead back into the connector to make the contact. Then I used heat shrink wrap to completely cover the resistor.





Second pic: here's the back of the AC unit. The brown bulb holder is installed in the lower left of the pic. You can see how the black shrink wrapped resistor sticks upward. You can always bend it carefully if there are clearance issues.





Third pic: Here are some sample LED/resistor combos I've soldered. That's how my shaved LEDs look using a cutting blade on a dremel. The two right ones are the LEDs with resistors wired into the bulb holders described above - the rightmost one without the heat shrink wrap on. The middle left one has the resistor behind the LED so you can drop it into the bulb hole and solder the ends to the cluster.




Hope that all helps.

Acuracy02

Thanks a lot for the pics. That last pic is the one I needed since the sockets you used for the A/C etc. are different than the sockets for the guage cluster. I am just going to be wiring the LED with some extra lead so that the resistor can be soldered prior to contacting the socket. Then I will have to shove a small piece of plastic or the like into the socket to keep the LED's secured. This might not make sense in words right now but I will post pics when I do this over the weekend. Wish me luck!

t0ast

I think I understand what you're doing. I don't think the resistor gets that hot, but be sure to keep the resistor from contacting any piece of plastic directly. With your plastic spacer thingee, I've sort of did that for some LEDs with the left-middle LED assembly by wrapping layers of electrical tape around the leads so the tape will fit snuggly into the hole. Good luck and post pics!

Acuracy02

What voltage is running to each of the bulbs in the guage cluster, anyone know?

From what this link says it seems like 14V, but isnt that pretty high?

Guage Cluster Link

Mike

t0ast

14V is what the alternator puts out when the engine is running.

Acuracy02

I'm trying to figure out the right resistor size to use is (I am wiring in parallel) (in terms of proper ohms). There is a calculator to figure this out here: LINK

but I am not sure what the voltage coming into each socket in the cluster on the TL is... it seems weird that it would remain 14v since that is what the alternator put out initiialy.

t0ast

If you're using 3 LEDs (blue, whites, NOT reds), then use 470 ohms for single LEDs and 150 ohms for three LEDs in parallel. Also, remember that if radio shack or whereever doesn't have the exact resistor, you can bump up the resistance to the next size up (never bump down) or more without really affectinig the light output.

If you're using the calculator, check the specs on your LEDs. They usually specify the forward voltage (eg: voltage drop across resistor) and the forward current in milliamps (mA). Try the calculator with 12V and 14V as the supply voltage, and you'll see that there's not really that much of a difference.

Acuracy02

Sweet deal. So I'll be doing 2 in a series so as long as I am above a 270ohm resistor on each LED it won't make a difference?

Good info, I think this thread will help out a lot of people in the future who hope to do some custom work.


Thanks for all your help t0ast

Acuracy02

I meant parallel

t0ast

Uh, are you doing 2 in series or parallel? If you're doing two in parallel, which config are you using:


--- LED ---
POS--Resistor--| |---- Neg
--- LED ---


--Resistor -- LED ---
POS--| |---- Neg
--Resistor -- LED ---

In both configs, you still use 560 ohm resistors since you're going from POS-resistor-LED-Neg for each leg. With the top config, you want 1/4 watt resistors, and I think the with the second, you want 1/2 watt resistors. But it doesn't hurt to bump up to a higher wattage resistor.

Bxscig

What does the wattage matter? To allow more current through?

wowzer

Please forgive my ignorance, but what benefit/value does replacing the original bulb with LED confer? Is it just to provide a customized color light?

Acuracy02

This...




That and it's cool to say i fabricated my own gauges.

Tatewaki

when I was looking for ways to mod my gauges, I found indiglo gauge does a much better job than modding LED

Acuracy02

This is the one I believe:

--Resistor -- LED ---
POS--| |---- Neg
--Resistor -- LED ---

Cathode on the LED goes straight to neg contact. Anode on the LED goes to resistor then to pos contact on the circuit board. Wired in parallel as pictured. One resistor for each LED.

Will it make a big difference if I get a lower resistor than 560? The calculator I used for 2 LEDs at 14V, dropped to 3.4V, 20mA suggests a 270ohm.

My LEDs came today, soldering will be done friday and sat i think.

t0ast

I agree with Tatewaki about the gauge cluster since they make gauges that light up in blue so its not really worth the time to do custom work. In fact, I have a set of those indiglo gauges sitting around for whenever I decide to do the LED conversion.


The wattage is the maximum power that the resistor can have before it blows. Its not really a problem with LEDs since they draw so little current. Basically:

power = volts x current = (12V) x (1 mA) = 12 mW --> 1/4 watt resistor is plenty


If you're doing one LED with one resistor between the POS and NEG, then use 560 ohms. When putting 2 LEDs into the calculator to get 270 ohms, you're wiring them in series. I don't know how to explain it other than in pictures. So schematically, I think you want the parallel config rather than the series config:

Parallel:
POS -- 560 ohm resistor -- LED1 -- NEG
POS -- 560 ohm resistor -- LED2 -- NEG
etc

Series:
POS -- 270 ohm reistor -- LED1 -- LED2 -- NEG


What matters is the number of LEDs in-line with each other between the POS and NEG wires. The calculator is calculating based on how many LEDs are in-line with each other rather than the total number of LEDs. You can use a single 270 resistor with a single LED, but it will cause the current to be too high (eg: 2X optimal current), making the LED brighter, but also reduce the life of the LED.