Hi all,
Over the past 12 months I have been fighting a digtial dash problem and I think I solved it. When ever my 1990 would run for at least 30 min. and the car was well warmed up (summer time in Florida), the numbers and icons in the display would scramble, disappear, and the re-appear. Half the time I did'nt know how fast I was going or how much gas I had. The problem would lesson on days that were cooler. After tearing apart the dash checking wires and harnesses several timee, taking apart the speedo and resoldering many of the connections the problem was still there. I even replaced the computer under the hood with no change. In the mean time I purchased a factory manual. I found that there is a seperate computer,behind the radio that controls all the interior electrical functions including the dash and speedo. One day I had the center dash apart I could see thecomputer and the wire harnesses connected to it, one of which is from the speedo. Because some one before me had cut away part of the inner plastic box that holdes the radio to mount a different one, I was able to get my fingers around the wire harnesses and push up on them to hopefully cause a better connection. Thedash computeris buried deep behind the center dash and access is usually gotten from the drivers side after taking apart many panels. Big Job! Bottom line, by mepushing onthe multi pin connectors I must of made a better connection because now the speedo works fine. I had to wait until now when things are hot out side again to be sure. So far so good! Hope this helps some one with the same problem.

 

That is great news!! I have the same problem with the gas gauge and speedo only mine stays scrabmbled all the time. When you say center dash behind the radio, did you mean behind the reciever or the radio under the passenger side dash?

 

The CCM (central control Modula) is located behind the radio receiver and the climate control. It sits vertically in a bracket with the pin connectors entering from below. It's about 6 by 10 inch's. I can get to my CCMthrough a holein the plastic housing that held theoriginal Bose receiver only because a shop cut away that housing to accommodate adifferent radio.I don't know what kind of space for your hand was there before they cut in holes? You may have to access it from the drivers side througharemovable panel and bracketstowards the top ofthetrany hump under the carpet according to the service manual.I highly recommend getting a shop manual. They are about $125 for the set but, worth every penny. It answered a lot of questions for me and saved a lot of time. Hope this helps. Good luck! By the way my vette is a 1990 coup. This procedure would only apply to 1990 and up with that kind of dash.

 

Thanks for the info Mike. As for the shop manual, does it have lots of pictures? I'm not very good at reading instructions without pictures. My vette is a 1991.

Charlie