HlhnEast

These LCDs are available at the same website listed above and on eBay by the same guy. Shop the website, the fleabay ones are $10 higher to cover the fees I guess. He has bulbs and different lenses to change the color of the display if you want. I dont like the monochrome look and there are multicolored ones available.

And yes, the procedure is the same on bulb replacement 84-89.

Good luck!

DinoBob

Picking up on this:

I need to replace my LCD illumination bulbs but would like to avoid removing the cluster. The Xenon bulbs recommended here require cluster removal as they have a different base and need new sockets.

Would this bulb work without changing sockets? It is a 5w 12v with the same socket type.

http://www.amazon.com/gp/aw/d/B008Y29LD8/ref=mp_s_a_1_4?qid=1385945299&sr=1-4&pi=AC_SX110_SY165_QL70

KYC4

Can you just replace the bulbs with LEDS? Perhaps a dumb question but I am curious.

Thanks,

Lee

DinoBob

LED light is directional so you would have to find bulbs that lit in the right direction. Also, LED just looks different and is not my cup of tea.

Cliff Harris

LEDs are like flashlights. They project a beam of light. To get around that the manufacturers sometimes make the plastic "cloudy" to spread out the light. Another method is to create an array of LEDs pointed in all directions, like so:



One thing to watch for is that LEDs need current limiting resistors or they will burn out. Some LEDs come with the resistors built in. These would be the "direct replacement" types made to replace a light bulb. If you buy individual LEDs then you will have to come up with your own current limiting resistor scheme.

I made my own LED replacements for the footwell lights. Notice how the LEDs are pointing in various directions to spread out the light. If you look closely you can see the current limiting resistor peeking out from beneath the LEDs on the left side. I bent the resistor lead to simulate the attaching loop of the original festoon bulb. The LEDs are held together with 5 minute epoxy. These LEDs are in my car right now and work great (nice white color instead of "incandescent yellow"):



I went through all this trouble before I found out about these guys:

http://www.superbrightleds.com/cat/l...acement-bulbs/

You can put in the bulb number and in most cases they have multiple possible LED versions in various colors. All of their LEDs have the current limiting resistors built in and some even have current steering diodes so they can be put in without worrying about polarity (LEDs are diodes and as such they must be operated with the correct polarity or they won't work).

jgalfo

I used this write up to replace my bulbs on saturday. great job easy to follow write up and pictures. I got replacement bulbs at Autozone for $11.00 and it took me about 4 hours which included driving to the local autozone after I got the origional bulbs out.

dash is working fine now

thanks,

John

KYC4

Thank you Cliff! I have a gent who is on the Ford Ranger forum that his LEDS are built facings in all directions, tested beforehand, have resistors and polarity is marked appropriately. I have used his LEDS in my Ranger and they works perfectly. Just was unsure if the digital dashes in the C4s are overly sensitive to a radically different bulb type or to LEDS. I know that heat is an issue when using bulbs.

Thanks for your help/info, sir!

Grateful,

Lee

Cliff Harris

One problem with replacing bulbs with LEDs is that they use completely different methods of creating light.

Bulbs are called "incandescent" for a reason. The filaments get white hot and emit light. The amount of light is proportional to the TEMPERATURE of the filament. The temperature is proportional to the voltage.

The brightness of LEDs is proportional to the CURRENT going through them. One other aspect of LEDs is that they have a voltage threshold. They basically don't emit any light until the voltage reaches a certain value. Then they suddenly start conducting and emit light. The current MUST be limited or the LED will burn out.

All this becomes important when you want to vary the brightness of the bulb or LED. With a bulb you can lower the voltage down to zero and the bulb will get real dim as you do so. Because of the voltage threshold with LEDs you can't do that. The only practical way to dim LEDs is to use PWM (Pulse Width Modulation). What that means is that you operate the LED at full voltage all the time and send pulses to it. A series of narrow pulses (basically brief flashes) will look dim. Longer pulses will make the LED look brighter.

It turns out that PWM also works with bulbs and we luck out because that is what the instrument cluster uses. That means that we can use either bulbs or LEDs and everything works. The trick is to get LEDs that are bright enough. The stock bulbs are REALLY bright, so that can be difficult.

I wrote an article on this very subject…

http://forums.corvetteforum.com/c4-t...ull-story.html

KYC4

Cliff, my thanks again for your time and advice/ideas, sir!

Grateful,

Lee

mako41

If you reread this thread you'll find the procedure to replace all the cluster backlighting bulbs, Xenon or Halogen, without removing the cluster. The Xenon T3-1/4 bulbs I linked to in this thread have the same wedge type base as the '89 OEM Stanley Xenon bulbs & the 882 Halogens used in clusters before '89, and fit right into the OEM sockets without any issues. The early year 882 Halogens tended to burn the sockets and boards after extended use and many times the bulbs and sockets they fit into need to be replaced because of heat damage.

DinoBob

882 bulbs do not have a wedge type base, sir. I checked this out quite carefully as I did not want to remove my cluster. Eventually I did and bought a full set of Xenons with sockets.

1bdvet

Nice job, when I had my C4, did the same swap, loved the brightness.

mako41

Actually 882 bulbs do come mounted into T2-1/4 wedge based sockets, and they will work fine for C4 cluster boards. Although the brighter, less heat producing xenon bulbs used by GM in '89 are definitely the way to go!

Here's one example;

http://www.1000bulbs.com/product/100...FWUOOgodHSYAtg

If you find you have T2-G4 Bi-pin bulb sockets on your C4, (you didn't say what year 'vette you have), the bi-pin xenon bulbs you linked to in post # 42 of this thread will work and you don't have to remove your cluster to install them. Just pull the old bulbs straight out and push the new xenon bulbs straight in as described in this thread.

StarleX86Vert

12w3q

petecaballero

Great write up, thanks. Before I tear into the dash, how do I know it is the bulbs? I hear that digital dashes have several different things that go wrong? My dash sometime works perfectly and other times it is completely or partially dark. A few taps on the dash with my palm and everything lights up temporarily. Sometimes the numbers go a bit crazy. Is this the symptoms of bad bulbs or worse?

BrandensBeast

Not sure what year your vette is but here is from 84-89, and if you have any problems Bryan is an amazing guy to do buisness with, he fixed my dash that had quite a few problems with it.
http://batee.com/corvette/dcrg/advancedproblems.html

petecaballero

Thanks, appreciate the info.