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87 LCD instrument Panel

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nickjgj

Guest
I need some info. I just got an 87 with the LCD instrument panel
I don't know if this is a common problem but I can barely read mine it seems like the contrast is wrong but I can not figure out how to adjust it also The Tach does not work at all and the speedo bar graph does not work but the digital part does anyone have any info or fixes for this thing?
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
Welcome To The Corvette Action Center nickjgj!

Glad you found us.

The dimness is probably caused by burned-out halogen bulbs in the cluster. They are fairly easy to replace; you just have to remove the plastic bezel surrounding the cluster, remove the thin silver reflective discs and you can pull the bulbs and replace them from the front instead of having to remove the entire cluster. Be sure to wear some latex gloves, or use the bag the bulbs come in, to prevent the oil from your fingers getting on the bulb which would cause them to have a much shorter lifespan.

There are four bulbs in the cluster if I remember correctly, and they cost around fifteen dollars each at a dealer. You can find them cheaper, and I'm sure a few people will chime in here about how you can save even more while having brighter bulbs - I just can't remember the part numbers now, and I don't feel like running a search.

As for the tachometer problem, it could be any one of of a number of reasons:
  • water in the bulkhead connector
  • defective tach filter
  • tach filter not grounded
  • engine not grounded to the uniframe
  • grounded wire going from the distributor to the tach filter
  • grounded wire going from the tach filter to the bulkhead connector
  • grounded wire in dash going to the cluster
  • defective cluster

The speedometer reading, or lack thereof, is most likely due to the bulb being burned-out. If your digital readout is functioning properly, then the bar graph should be functioning as well.

A book that comes highly recommended for troubleshooting and repair of the digital display cluster on the 1984-1989 Corvettes is Gordon Killebrew's "1984-1989 CORVETTE DIGITAL CLUSTER -- A Complete Step-by-Step Operational and Troubleshooting Guide". ;)

I hope this helps you.
 

Korcsmoros

New member
Joined
Apr 6, 2002
Messages
2
Location
Flint, MI, USA
Corvette
1985
Tachometer troubles

I have a question regarding the Tach filter on my '85.
I was ready to send the entire cluster in to get an overhaul and was calling many sources. They were all ready to accept the entire cluster until I contacted Southern electronics. The folks there listened to my delima and described the possible fix.
The problem that I am having is that at normal temperatures the tach does not work at all. Under very high temperatures (hot summer day in Michigan) the tach would work intermitently.
My question is regarding running without the filter. I would like to trouble shoot the problem and be certain that this is the problem before I go through the replacement. Is there any damage to occur if I run without it?
Also I have had some problems with intermitent dimming of the lights. I replaced all of the lights and found the replacements that I purchased have a tit at the end of them that do not allow for replacement of the cover. While replacing them I found that with some finnesse they would light. It appears that the sockets are loose, this will require access from the back I believe.
Is there a particular brand of bulb that does not have the tit on it. do they make a tool for removal and replacement? My fingures just don't fit well. I was also warned about the contact with the bulbs and the longevity of them.
Again a big thanks to SOUTHERN ELECTRONICS for steering me in the right direction. and another big thanks to CAC for some more technical assistence.
 

MoeJr

Well-known member
Joined
Jun 7, 2002
Messages
797
Location
Londonderry NH USA
Corvette
Vetteless
When I bought my 84 my display was dim just like yours. On mine the bulbs were fine but the display boards needed some rebuilding. My electronics wizard friend rebuilt mine for 250 bucks and saved me 150 over the cost of sending it out. Works perfect. I would have the whole unit gone thru.

:beer
 
E

Eagle85C4

Guest
I can rebuild tach filter for you....send me an email...
 

Korcsmoros

New member
Joined
Apr 6, 2002
Messages
2
Location
Flint, MI, USA
Corvette
1985
Repair complete

I just wanted to let all know that the repair of the Tachometer Filter went well. And all seems to be in working order today.
Special thanks to Eagle85C4
price was above reasonable, turnaround was as aspected, and initial results are "two thumbs up"
Thanks again to the CAC for some help in keeping my friend in top running condition.
 

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