Light Bulb or LED???

**'89AccordLX(Rus)** · 03-12-2003, 05:23 PM

Hello everyone,

Since my heater control LEDs were not working for a while I finally got around to it and resoldered the contacts for those. In addition to that, my illumination for the fan setting and the A/C button (note: not the ON indicator) are also not working. I tested the lights for continuity and found that they lacked such. However there is continuity between the light contacts and the contacts on the I/C boards. My conclusion is that these lights are simply shot.

The question now is whether or not these lights are LEDs or actual lightbulbs? Are these lights only available from a Honda dealer or can they be found at Radio Shack (or another similar store)?

Thanks in advance for any input on regarding my questions.

3axap.

**DBMaster** · 03-12-2003, 07:44 PM

The actual green or orange lights that tell you which function is active (i.e. vent, heat, fresh, recir) are LED's. The lights that illuminate the buttons at night are light bulbs. I know because I replaced the one that lights up the "A/C" button at night. I used a little 12v bulb from Radio Shack (better prices at an actual electronics parts place - Tanner Electronics in Carrollton is great).

There would be some modification necessary to convert those to LED's as LED's are lower voltage (5v, I think).

**dosh8er** · 03-12-2003, 08:07 PM

screw that lamp $hit! Just go to radioshack, or whatever (i personally find www.mouser.com a very good site) and find some regular square 5v LED's (of your desired color). Hell, they can be any friggin' color, whatever you like. Just notice how the old one came out, since LED's have polarity. (+ and -).

IF you do go buy new LED's, here's a great picture to aid you... just REMEMBER how the old one's went in!

**ACCORD EX** · 03-13-2003, 04:45 AM

radio shack all the way !

MIKE

**'89AccordLX(Rus)** · 03-13-2003, 01:41 PM

Thanks for the input guys!

I have decided to replace the illumination light bulbs (only burned out ones) with LEDs. I compiled a small list of the items I will need.

LEDs:

Blue LED (for A/C button backlighting):

Output: 2600 MCD
Input: 20mA at 3.7v
Radio Shack number: 276-316
Resistor needed to reduce voltage: 540 ohm

White LED (2 needed) [for the Fan and Air Temperature Sliders]:

Output: 1100 MCD
Input: 20mA at 3.6v
Radio Shack number: 276-320
Resistor needed to reduce voltage: 545 ohm

Resistors:

330 ohm resistor used in combination with a 220 ohm resistor will produce the required resistance of 550 ohm (the ohm value must be within a 15 ohm range of the ideal calculated value)

330 ohm 1/4W 5% resistor:

Radio Shack number: 271-1315

220 ohm 1/4W 5% resistor:

Radio Shack number: 271-1313

Now for the electrical gurus on this board: Can you please tell me if I have this setup correctly? The LEDs seem to have a pretty high output. Will this be too much for backlighting the buttons and sliders?

Thanks again for the help.

:pimp:

3axap.

**ACCORD EX** · 03-14-2003, 02:28 AM

are you doing your own circuit ?? why don't you use the one there ! ?

MIKE

**DBMaster** · 03-14-2003, 09:17 AM

Here's a question for those of you who have done this. I have only had one illumination bulb ever burn out and I just replaced it. Resistors put in a circuit like this get pretty hot. Where do you mount them to prevent any plastic form melting as a result?

***AZmike*** · 03-14-2003, 09:51 AM

My fan speed light bulb went out when I resoldered my LEDs too. Those little bulbs are pretty bright so I doubt it will be too much backlighting.

**2twisty** · 03-14-2003, 10:25 AM

I put LEDs in the AC panel of my Miata.

You can see them here:

http://www.linuxpupil.com/2twisty/

It was fairly easy to do, and no, there have been no issues with melting, because LEDs draw so little power, the voltage drop is not very high.

Id' say that the light bulbs get hotter than the resistors do.

I can't remember exactly which size of resistor I used...but make sure your resistor is big enough to handle it if the car's voltage goes to 14.1 or higher (when the alternator is charging the battery) or you could wind up popping the LEDs, and causing yourself a whole lot more work.

Good luck.

Chad

**DBMaster** · 03-14-2003, 10:47 AM

I can't remember exactly which size of resistor I used...but make sure your resistor is big enough to handle it if the car's voltage goes to 14.1 or higher (when the alternator is charging the battery) or you could wind up popping the LEDs, and causing yourself a whole lot more work.

That's why I stuck with a bulb. Plus, for this application the LED might not be as good because the bulb puts out omnidirectional light while the LED is pretty much straight ahead. One bulb burning out on 14 years is not such bad performance.

**'89AccordLX(Rus)** · 03-15-2003, 06:12 AM

Well, I finally took a trip to Radio Shack and got all the required items. The only change from the original plan was the use of a single 560 ohm resistor. The air conditioner backlighting was the toughest to change.

The bulb used there is much smaller than the 5mm LEDs I got. The only way I got it to fit was to get rid of the little plastic bulb-holder and simply put the LED into the hole in the circuitry. The stock IC terminals for the bulb could not be used so I had to solder my own connections for + and - to the light pins that go to the connector. The fan setting and temperature controls were easier (I changed both bulbs to LEDs here so that the lighting is uniform). I simply removed the original bulbs and stuck the LEDs in place, then soldered the reisistors on. The illumination is much brighter now but not too bright where it is a huge difference with the stock lights. Thanks for everyone's input!

P.S.: The formula to figure out the resistance value for the resistor is: R=(Input Voltage - Required Voltage)/Amps

3axap.

***carotman*** · 03-15-2003, 06:43 AM

Do not use leds if you want your dimmer switch to work again. LEDS cannot be dimmed.....

**'89AccordLX(Rus)** · 03-15-2003, 07:00 AM

carotman,

What kind of a setup with LEDs are you talking about? I just went out to my car and played with my dimmer and all the lights INCLUDING the LEDs are dimming properly. Maybe we are talking about different ways of installing LEDs here.

3axap.

**ACCORD EX** · 03-15-2003, 09:09 AM

Originally posted by carotman
Do not use leds if you want your dimmer switch to work again. LEDS cannot be dimmed.....

why carotman ?? isn't a LED > Light emmiting diode ??

MIKE

**MrBen** · 03-15-2003, 09:51 AM

LED's do not burn out because they don't have a filament that burns out. Their plastic bulb makes them a lot more durable. They also fit more easily into electronic circuits. LEDs generate very little heat and won't ever need to be replaced, but, as for dimming, I do not know, but it seems possible!

**dosh8er** · 03-15-2003, 11:20 AM

IT IS POSSIBLE to dim LED's!!! Dimming is, what? Changing the voltage going to the desired application..

BTW, Originally when i posted, I THOUGHT this was about replacing the LED's behind buttons, however I was wrong. SO now, I seem to take an opposing stance. I think that a bulb is damn fine. Even though LED's last longer, like DBMaster said, they do not have a "brighter" appearance versus their counterpart, the lamp.

I do not think it is wise to use LED's with your present circuits without a proper voltage modification. It would make sense that the old lamps run on 12v, and I doubt there is an LED that likes that too much. ( I believe nominal voltage is 3vdc, transient is 6ish ? and max is 9vdc.)

I seem to think it would be not wise to run the LED's at the old voltage on which the old lamps ran.

AND PLEASE, don't tell me that you can change the voltage in the circuit from 12vdc down to whatever the hell voltage it is with whatever the hell resistor(s) setup!!! Electrical circuits DO NOT WORK in that way. The only way to step DOWN voltage is through a transformer. Please, I'm sure of this! I worked the math, and experienced. (if anyone would like to refute my claim I would be more than willing to show them proof that it doesn't work!)

Anyway, It's cool that you got em in, but I'd be wary of those LED's since they may not be operating at proper voltage. You could probably check the current (no pun intended) voltage of the curcuit by using a voltage meter (multimeter), if you don't have one, radiohack is a place to get one... or order the mother of all, the $50 one from Sears, which has temp stuff and many more functions as well.

**MrBen** · 03-15-2003, 11:46 AM

LED's will NOT blow, therefore running at a HIGHER voltage is not going to drastically effect it.

Oh, and you're wrong. You said "electircal circuits do not work that way" and "the only way to step down voltage is through a transformer". Converters can be used for electrical items. They simply step down the voltage. While they are not as efficient and easy to use as transformers, it IS another way to do it.

**'89AccordLX(Rus)** · 03-15-2003, 12:26 PM

OK,

I am not in any way questioning your opinions and experience with electronics, but LEDs do blow out because they are designed to be used only with certain voltages. Now there are some 12 volt LEDs available for higher prices if you don't want to go the resistor route.

Here is a link to a site that I used to calculate the proper resistor value for my application.

http://www.bit-tech.net/article/68/

Thanks for your input.

3axap.

**MrBen** · 03-15-2003, 12:40 PM

I did not directly relate blowing due running to higher voltages. I was saying that LED's are deisgned to not blow because it does not have a filament like that of a light bulb. Anything is going to blow if enough power is put to it. Sorry for the confusion.

**dosh8er** · 03-15-2003, 03:12 PM

Originally posted by GhettoAccord
LED's will NOT blow, therefore running at a HIGHER voltage is not going to drastically effect it.

HAVE YOU ever put 12vdc through a 3vdc rated LED? Believe me, they DO blow. There's a reason they print that crap we humans call words and numbers on the back of the packaging! You are thinking that slicon devices are just fool-proof and designed specifically to carry that change in refluctuation in the circuit. YOU are wrong. Filaments vs. LED's has nothing to do with 'blowing' the item in question. LED's are Silicon based devices, and do not use inert gases as lamps do. Just because it says "LED" doesn't mean $hit! It all boils down to the desired application.
Converters can be used for electrical items.

Originally posted by GhettoAccord
Converters can be used for electrical items. They simply step down the voltage. While they are not as efficient and easy to use as transformers, it IS another way to do it.

Please enlighten ME oh wise one!

What the hell are you talking about? Please be more precise. What is in a convertor circuit? Does a convertor circuit not have some sort of coil/transformer in it? Please, I'd like to see a circuit like this without a transformer and have it produce the desired output!! It just seems to me that a transformer would be the cheapest and simplest method of dropping voltage.

***carotman*** · 03-15-2003, 04:24 PM

ok I was wrong guys

I was thinking about something else

**MrBen** · 03-15-2003, 04:37 PM

I already corrected myself, so please dont waste your time trying to make yourself sound smart. Perhaps moving your eyes up another inch (if that's not too much work) would suffice.

Transformers ARE the cheapest and simplest method of dropping voltage, but there ARE other methods such as CONVERTERS. You dismisssed all other methods right off the bat and that was wrong. I am not going to waste my time explaining shit to you being as you are obviously arrogant and all knowing. All hail ye. Unlike you, I am ADMITTING I WAS WRONG. Get over yourself. If you want to know more about converters, how about moving your fat stubby little fingers and typing it in a search engine.

If you want to start your research, try this site. This is one of many sites explaining it, and there are many types of converters for different types of uses. I'm not saying at all this will work in your car, and I never did.

http://www.eurogroup.gb.com/voltage_converters.htm

***A20A1*** · 03-15-2003, 10:35 PM

I think you guys realize your arguing ain't getting you know where, answer the guys question and be done with it. This thread stay open though uless you guys decide you can no longer control yourselves.