mixalive

I noticed yesterday that the digital part of my instrument cluster is dropping out then coming back on my 92 Base model.
Let me clarify: It appears the LCD part of the instrument cluster is losing its data intermittently. The bumps in the road seem to trigger it.
Has anyone experienced this? Any suggestions on what approach I should take for diagnosis?

Thanks

corvetero

Same to me on my 92, I noticed mine do it after about 30 minutes running and dissappear when pushing the dash a little. I guess might be a misconexion issue in the LCD back.

mixalive

I know it's been a while, but I am just now up to dealing with the display issue I am having with my 92. I shot a short video with my iphone and posted at the following Utube link. The first part of the clip is me at idle, lightly hitting the top of the dash with my hand. The latter is driving down a rough road.
Things to note: The power to the display seems constant but the data input gets disturbed by the vibration of the road.
Enjoy the clip and please give me your input.

corvetero

Thank you man. 100% same problem than my 92.

Actually, after some time without problems, I suffered it again yesteday. I've realized that if you push the speedometer, by the upper side, the problem disappear, then I figure out it might be a problem with the connector.

What do you think about?

mixalive

I am thinking either a bad connection at the point in the LCD that is receiving the data, or a cracked solder joint within the LCD.

mixalive

I guess since no one is chiming in, it must be something painfully obvious.

I plan on pulling the speedo cowl, pull the display forward while connected and wiggle some cables while energized to see if I can isolate the problem. If it is not in the cabling at the connector, thump the display with my finger. If indication of problem with the latter, pull the display out to attempt to repair cracked solder joint or replace.
My clear speedo cover needs a good polishing due to a scratch and a little hazing, so I plan on doing that at the same time.

wschmidt

I am having the same issue on my 93, started about 2 weeks ago. I havent had any time to deal with it yet, just suffering through it for now. It does seem to be a connection issue, mine even went blank for a minute or so and came back with all the data still in tact (trip, milage, etc). Do you have the service manual? I have no time to dig into this myself, but section 8A-82-11 chart 14 describes the troubleshooting for this issue. Says check CCM for codes 26,27,31,32,33,34,35, or 37 as the first step so it could be a CCM (which supplies the data) issue. Going to be a long time until I have the time to dig into the instrument panel, so I would be curious as to what you come up with.

mixalive

I have successfully repaired the situation with my LCD drop out sttuation and this is how I did it:

Removed the instrument cluster: Basically have to drop the steering column and work the bezel, clear screen, then the cluster out. The connection automatically disconnects when you pull the cluster as the connection is a multi-pin mating disconnect.





I removed the LCD by working the red connector back and lifting the LCD out. Inspected the assembly for any pushed pins, sprayed the pins in connector and LCD pins with Caig DeOxit and re-installed.



I suspected a cracked solder joint on the circuit board on the back of the cluster.


These things can me somewhat microscopic, so instead of trying to find the cracked joint, I opted to re-solder all the pin connection joints related to the LCD and the multi-pin connector. Remember to work on an anti-static surface and ground yourself to the cluster. The proper way to re-solder the joints is to use a solder sucker or solder braid to remove the old solder and re-flow new solder in. All I did was flux the joints and flow new solder into the existing solder at about 650* F using a pencil tip on my Weller solder station. The pictures indicate the areas I concentrated on.




I finished off by spraying the pins in the male multi-pin connector with De-Oxit. Re-assemble the cluster. I took the opportunity to polish the clear bezel while it was apart using Blue Magic Headlight Restorer plexi polish. Not forgetting to spray the female multi-pin connector in the dash. Re-installed into dash and test. Everything A-OK..

Tx_94vette

My 94 base, has a similar issue only banging on it, or bumps does not change anything, the lcd just comes and goes eratically, is there a trick to getting the glass out, it kinda held down on the side, I`m afraid I will break it

mixalive

I don't know. Mine came out easy after removing the bezel and the screws holding down the plexi. You do have to drop the steering column.

truggiero19

Thank you for the excellent explanation here. I am having the same problem with my '93. I have been tolerating it for some time now but it has been getting worse and worse. Now it will turn off completely for entire trips sometimes and not come back no matter where I bang on the dash or push on the cluster.

Thank you for your help.

cshuman

I've had the same problem. I have a 91 with the same digital dash. Heres what I found, as a matter of fact I just got thru having to do it again. It happened to me about 6 years ago. What I found was a bad connection at one of the wire harness plugs that goes into the CCM. The CCM is located behind the radio. You have to take the drivers side knee bolster out then there is a plate that supports the left side of the CCM that has to be removed. To make it easier I removed the drivers seat also. It is not easy to get to. If you have a helms manual it will help.

Once I got it out I sprayed both the CCM contacts and the connector with contact cleaner. Then I took a small modeling paint brush and applied some Di Electric grease to the contacts on the CCM with the hope that this want happen again. Then reassembled it. If you get into doing this you can get it apart to the point where you can touch the plugs going into the CCM while you have the dash active and move the plugs, if that is the problem you see it come and go.

I went thru this a while back and first removed the dash and sent it off to have it rebuilt with no help.

mixalive

Great info.

Tx_94vette

a fellow member sold me a used lcd display for $40 and that did the trick, she has been a good girl ever since

mixalive

Do the procedure on your old one and have a spare or make some money.

mixalive

Repair your failing LCD.

kkelly124

I know this is an older thread and I don't know if this will help anyone in the future. I just had this same thing start happening to mine. It was happening with my old worn out cluster and the new one I installed as well. So I ruled out the cluster itself. I then remove the floorboard cover and started moving wires and watched it go in and out. For me I am about to make sure my plug in the back is making a good connection or if it has loose connectors and then to trace the wires from the plug and see if I can locate a single culprit.