I am having a problem with my '84 digital dash. The digital readings do not work, the entire speedometer, tachometer and the fuel gauge do not work as well. All fuses are new, the entire dash lights up, just have no readings.

I have heard the motherboard could be dirty, bad ground or the computer is going out. Anyone else had this problem? Any suggestions? Don't want to tear everything apart if I don't have to.

 

Check out this site on How To repair your C4 digital dash:

http://batee.com/corvette/dcrg/repai...tor/repair.htm

OR, you can send your unit to Contemporary Corvette and they'll repair it for you.

http://www.contemporarycorvette.com/

 

[QUOTE=pmihaltian;1580020187]Check out this site on How To repair your C4 digital dash:

http://batee.com/corvette/dcrg/repai...tor/repair.htm


I went this route and with patience, some replacement parts & cleaning I finally have mine working great.
The diagnostics and step by step repair guide are really straight forward.

 

I have the same problem with my '86, i've read alot on it but i can never find anyone with the same symptoms as me, until now.

 

I am no expert but I would say if every readout isnt functioning, your LCD power supply is shot. Time to send it out for repair.

 

i had the same issue the lcd polarized are uv damaged...you can try replacing the lcd film but i ended up breaking one the lcd's those lcds are on ebay or vettesport.com actually sending out for rebuild by vettesport is the best bet... wish i did that first!

 

I finally removed my cluster.

Upon removal I noticed that one of the connectors was very loose so I placed it firmly in and started my car. Had to take the chance that it was just a loose cable that was causing my problems. Unfortunately that was not the problem. But, because of the angle of my cluster I found that I could see the digital readouts and everything else that was previously not seen at all. I couldnt see it well though, it was very very faint.

There is a tag that says its a certified remanufactured part from 1997. The motherboards are very clean and look almost new. The LCD's look great.

Because of all that and the fact that my custer does not go completly black when the car is off, it was suggested that I more than likely have UV damage. So I have purchased some replacement film from polarization.com that is supposed to be specifically for such instances.

Has anyone done this before? Any tricks of the trade? Thanks in advance.

 

Wait, you could see the readouts??

This is different than the gauges not working.

Do us a favor, take a flashlight and shine it into your cluster and see if you see the green bars from the tack going up and down....

If you do see the bars, then you have a "back light" issue caused by a short....

Using Batee.com you can fix this problem easily for less than $50 in a single afternoon.

OR

You could send it out.....$$$$$

 

The flashlight just made it light up as if it were day. Still couldnt see the bars or the digital readouts.

I am assuming that you are talking about the four bulbs that light up the cluster when you say "back light". All of those work and obviously the sensor works as when I turned the flashlight off it dimed again. If not please elaborate.

 

^^Ah, that is different from a "grounding issue" that is so common with the C4 cluster.

I'll back out as I haven't a clue as to where to tell you to look for this gremlin.

Still, If I were you, I'd peruse batee.com, that guy posted up a bunch of tech tips for C4 Clusters....I may not have looked for you specific problem as I wasn't interested, but that doesn't mean that Batee didn't address it.....

 

 

Once installed update us to see if that fixed the problem as that is probably whats wrong with mine aswell.

 

 

based on what your saying happened with the flash light, it sounds to me like the photo sensor in the top left of the cluster is the issue.

 

Finally received the film and took apart my cluster. The old film was was uv damaged. It had an orange/brown tint to it and was brittle. A little time, a razor and some patience and everything went according to plan. The center one caused me some problems as it had 3 layers that I had to pull off. No idea why as the other 2 only had 1 layer...

Couple tricks; When taking off the old film use the razor to start a corner, slowly peel and when it starts to stick use your razor until it starts peeling normally again. Will take a little extra time but you wont have to worry about a lot of clean up later. Mine were really stuck and I had to pull fairly hard so be prepaired just incase yours is the same.

On the new film only peel a small amount of the protective film off the back. Line up the top and as you peel off the clear film slowly run your "squeegy" along with it. I did it this way and only ended up with 1 tiny bubble between the 3 and no finger prints. Dont forget to peel the front protective film off once you're done. Total time from start to finish 1 1/2 to 1 3/4 hours; not including getting the cluster out of the car.

You will need 2 sheets if you are ordering from polarization.com to cover all 3 they are only 10x6 and will only cover the speed and tach or the center and one other. It has anti-glare and a hardcoat to help resist scratching. It will run you about $57; $24 per sheet and $9 for shipping I got my 3 days after ordering.

So far it looks like that was my only problem. The cluster is back in my car and has been working great.

 

Just incase anyone is interested:

-Cluster lit up when car was turned on. At night if you shined a flashlight on the sensor the cluster would brighten and then dim again upon turning the flashlight off.

-None of the readings worked; digital or bars and the cluster did not go completly black when ignition is off.

-All fuses were new

-Removed dash and cluster but kept cluster plugged in. In order to do this the cluster was at about a 45 degree angle. Turned ignition on (didnt start the car) could faintly see the digital and bar readings. Turned car on and reved the engine, could faintly see the bar move. Turned the car off and disconnected the cluster.

-Took it apart checked the motherboards to make sure they didnt need soldering anywhere, checked LCDs for cracks, cleaned the rubber connecters and replaced the polarized film, connected it back up to car and it works great now.

Good luck for anyone else who has this problem.

 

Just had a guy say he would fix for 300$ shipping included, but after hearing this thanks for possibly saving me 250$. This sounds like the exact problem mine has. These forums are great