Anyone put LED BULBS in the Dash Cluster yet?

[74Chevy74]

I've got a tach dash I'm getting ready to install in my truck, so I ordered a new lens for it, and was thinking of upgrading all the bulbs to LED. Has anyone done this? I searched the board but only found stuff on led tail lights.
The other problem is they make about 5 different bulb combo's and I don't know which one would be best? they have single led, 4 led, 6 led, and some wide angle one. ANYONE????

[N2TRUX]

I haven't done it but I would think the wide angle LED would be what your after. Since most LED's are cheap get a few different ones and try them. Report back and tell us how it went...

[hotrodhomi]

didn't someone do a write up on this a while back?

[FLAGG]

Yeah, there was a writeup a while back. I don't have the link handy, however. I'll do a little digging and see if I can find it.

[chevychic]

That would've been me.
Haven't been on the board in forever....

You can see my write up at http://webpages.charter.net/chvchk/ledinstall.html

[chevyjr73]

i don't think he's talking about a whole LED conversion but the new LED replacement bulbs you can get that go in place of the factory bulbs.

[chevychic]

I was referring to the write up. I posted it over a year ago.

I'm not sure, but I'd be surprised if you can dim those LED's that plug into the standard bulb socket with the standard dimmer switch. LEDs require a wider range of resistance than a stock dimmer switch provides for filament bulbs to get them to dim. Otherwise they're either on or off.

[FLAGG]

Yeah, I have a few bags of the plug in replacements I bought over a year ago (red and white). If I remember correctly, I jammed a few into the stock locations and the dimmer didn't do anything for the LEDs. I believe I have your writeup printed out somewhere, and I bought a bunch of the parts to make a new dimmer, however apathy owns me.

[Zoomad75]

I've been thinking about doing the full LED thing on my cluster when I upgrade to my tach cluster. I've read Chevychic's write up a while ago. So from that I understand the need for the dimmer to have a different resistance range due to the lower internal resistance of the LED's.

I was at the boneyard the weekend before last and picked up an extra headlight switch for expermintation purposes. My first thought was to add another rheostat in line that would be gear driven off of the knob shaft. Howver after looking at my spare, it would be complicated and probably not very durable. Thinking more about it, my next Idea is to install a resistor inline to the dimming circuit. I'm not sure how much resistance to use though. My thought is by adding resistance to the circuit, you take your existing resistance value and move the range higher up the scale depending on the amout you add in.

For example (don't quote me on values as I haven't put my ohmmeter to it yet), lets say the stock dimmer works through a range of 0 to 100 ohms and that's fine for stock incandecent lightbulbs. by adding say a 500 ohm resistor your values for the dimmer would be from 500-600. You still have a 100 ohm range, but now it starts 500 higher.

What I am not sure and will find out when I test it is, would cutting the availble voltage to the LED's by and extra resistor also limit the maximum brightness of the LED's at the full high setting? My other concern is how much heat might the resistor generate? I don't want a possible fire hazard by a resistor getting too hot.

My goal is LED lighting that works off of stock looking controls. I'm kicking around using UV (blacklight) led's for a real stealth look that just the needles and lettering pick up the light. I might get a set of white or blue too just to see what looks best.

I'm welcome to input if my idea seems off base. (it's 5:40 am for me right now)

[LOHRTBT]

I toyed with it a bit..Like Ken said..you are gonna need Wide angle ones..the others are way too pinpointed and dont look right. They are however bright as hell!

[chevychic]

If you're bent on using the plug in replacement LED's and don't mind not being able to dim your cluster, just take some sandpaper to the head of the LED. This will cause the light to diffuse thus - wide angle. You could also grind down the top of the LED to take it from a curve to a flat with a dremel. This also spreads out the light. Just be careful not to hit the diode inside. When I did this on my cabby, I experimented with both and ended up grinding off the curve of the LED casing.

Robz- The biggest problem I see is that it's a range issue in the design of the switch (potentiometer). If you place a resistor before the switch, you still have the same range, just at a higher resistance which is cutting the power to the LEDs. It was this lack of range that I had a problem with. I just did not have a large enough range to provide a high enough amount of resistance to dim the LEDs adequately and provide a low enough resistance to achieve full brightness. For 2 5MM LEDs running off 12v with a 3.6v drop across the LED, the resistor value required is 270 ohms. If your maximum brightness setting on your switch is higher than 270 ohms after you wire in a resistor, you will not be using your LEDs at maximum brightness. When I was doing this to my truck, I had all the specs for the dimmer resistance and such but it was so long ago, I've forgotten. If you find to have the same problem and want a range of dimming capabilities, to keep with a stock look you could hide the potentiometer somewhere like in the ashtray or such.
I've never had or heard of a problem with heat and resistors. Capacitors and voltage regulators, yes. If you do find it to be a problem, you could get yourself a project box to place a board in with your resistor(s) on it and get yourself a small heatsink.
As for the blacklight look, lsdiodes.com carries a UV LED. I received a couple freebies with an order I placed but have never used them. I found that the blue LED puts a nice glow on the whites of my needles. Of course, the pics I have don't do it an ounce of justice. It looks sweet in person.

[Prerunner1982]

glad you still visit us once in awhile sweetie...enjoyed our chat the other night..

[chevychic]

Originally Posted by Prerunner1982

glad you still visit us once in awhile sweetie...enjoyed our chat the other night..

I'll try to come around more often. As long as I stay off the GD board. I was getting fed up with the dating game going on in there with some of the other female members. I thought we were here because we love our trucks???

I saw the LED thread and had to chime in

[Prerunner1982]

Originally Posted by chevychic

I was getting fed up with the dating game going on in there with some of the other female members. I thought we were here because we love our trucks???

Hmm i must have missed that one...

so Heather, when are you going to work on good LED taillights for these trucks? (had to keep on subject, haha)

[bigblock73]

Originally Posted by Prerunner1982

so Heather, when are you going to work on good LED taillights for these trucks?

I second the motion!

BTW, glad you made it back Heather...was wondering if you left us for good.

[Zoomad75]

[QUOTE=chevychic]
Robz- The biggest problem I see is that it's a range issue in the design of the switch (potentiometer). If you place a resistor before the switch, you still have the same range, just at a higher resistance which is cutting the power to the LEDs. It was this lack of range that I had a problem with. I just did not have a large enough range to provide a high enough amount of resistance to dim the LEDs adequately and provide a low enough resistance to achieve full brightness. For 2 5MM LEDs running off 12v with a 3.6v drop across the LED, the resistor value required is 270 ohms. If your maximum brightness setting on your switch is higher than 270 ohms after you wire in a resistor, you will not be using your LEDs at maximum brightness. When I was doing this to my truck, I had all the specs for the dimmer resistance and such but it was so long ago, I've forgotten. If you find to have the same problem and want a range of dimming capabilities, to keep with a stock look you could hide the potentiometer somewhere like in the ashtray or such.
I've never had or heard of a problem with heat and resistors. Capacitors and voltage regulators, yes. If you do find it to be a problem, you could get yourself a project box to place a board in with your resistor(s) on it and get yourself a small heatsink.
QUOTE]

I was afraid of that. THe thought sounded good to me at the time. I don't have a problem with a second potentiometer, just where I might put it. I can hide it if I need to. Just need to get some LED's and start tinkering...

[boxrodz]

I probably take a different approach to dimming the LEDs.

I'd drive the LEDs with the correct forwarding voltage to guarantee that the LEDs are operating in the correct voltage range (and for optimum brightness). As chevychic said, LEDs are either 'on' or 'off'. To create the dimming effect, use a PWM (Pulse Width Modulator) instead. They use a pot(entiometer) that allows the user to vary the duty cycle. By doing so, you can change the frequency and length that the LEDS 'blink' on and off. The cycle in which they blink is not detected by the eye as a blink, but more as a dimming effect (so long as the frequency is not set too low). They can be had for $10 to $15 or one can build one for a bit less.