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Old 11-02-2011   #1
SteelBlueZR1
 
Join Date: Aug 2011
Location: Evergreen, Co.
Posts: 346
Exclamation Dim Dash LCD Speed Display

Has anyone else had an issue with the LCD Speed/Gas gauge display being dim and gray vs. showing dark black digits? My car has very low mileage, and i wonder if there is corrosion on the pins on the back of instruments vs. grounds making bad contact. I notice that the LCD backlight dims when I press on the brake pedal at idle.

Where are the grounds for the instruments located and how do you access them to clean them? I read about someone who just cleaned the pins on the back of the instrument pane with alcohol and the connector and the display is now dark uniform black. Any sage input or solutions before I proceed to remove the instruments is appreciated?
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1991 ZR1 Steel Blue / Steel Blue
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Old 11-02-2011   #2
Kb7tif
 
Join Date: May 2009
Location: S Nevada
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Default Re: Dim Dash LCD Speed Display

The lcd portion wears out. I have 3 exact same replacements and All have a different brightness.
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Old 11-03-2011   #3
SteelBlueZR1
 
Join Date: Aug 2011
Location: Evergreen, Co.
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Default Re: Dim Dash LCD Speed Display

Thanks for the feedback on this issue. In case I clean the contacts and grounds (does anyone know where the instrument grounds are exactly located?) and I still have very light LCD speedo numbers, are any of your LCD panels available for sale?
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1991 ZR1 Steel Blue / Steel Blue
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Haibeck chip, slotted rotors, camber brace, C-beam plates, OBX exhaust, Nitto NT555 tires
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Old 11-04-2011   #4
ZR1@gmx.com
 
Join Date: Oct 2010
Location: Sedalia, MO
Posts: 150
Default Re: Dim Dash LCD Speed Display

My display has started dimming as I drive it... It slowly flashes from bright to dim, I hope to learn how to fix this too!
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Old 11-05-2011   #5
RICHARD TILL
 
Join Date: Aug 2005
Location: Iuka, Mississippi 38852
Posts: 756
Default Re: Dim Dash LCD Speed Display

Me 2.
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Old 11-05-2011   #6
captcorvette
 
Join Date: Jan 2011
Location: Dubai, United Arab Emirates
Posts: 449
Unhappy Re: Dim Dash LCD Speed Display

Add me to the list. This same issue happens on my '90 ZR1 and my '90 & '91 roadsters.
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Old 03-14-2012   #7
SteelBlueZR1
 
Join Date: Aug 2011
Location: Evergreen, Co.
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Default Re: Dim Dash LCD Speed Display

So, I finally cleaned any corrosion on the pins on the back of the instrument panel and the connector with alcohol and steel wool, but the digital speedometer display is still dim. Has anyone else come up with a solution for the dim speedometer LCD display? I still plan to clean the ground at the driver's side foot well/speaker cover.
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Bert Rankin
1991 ZR1 Steel Blue / Steel Blue
#1029
Haibeck chip, slotted rotors, camber brace, C-beam plates, OBX exhaust, Nitto NT555 tires
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Old 03-14-2012   #8
Kb7tif
 
Join Date: May 2009
Location: S Nevada
Posts: 352
Default Re: Dim Dash LCD Speed Display

The display gets weak, I have 3 over here and have 3 different brightness's
from almost unreadable to normal. All from the same car.


See if you can swap out a known good unit.
Ive been thru all of this- its rarely grounds
or this kind of thing.
All of the functions ( digital segments ) are controlled by the CCM and Pcm together. As far as anything but the backlighting .That rarely goes out.
Try a known good unit.
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1995 Convertible Supercharged Auto
1974 454 550hp (avatar car) On the blocks- -Scharger install !
1992-Zr-1 Sold.
Watson Headers
Ported Plenum, Housings
Random tech cats
Fidanza Flywheel
Chipped, Relocated Mat
Woods 165 stat
Borlas, Straights
1996 Lt4 Sold
1994 Lt1 Sold
2004 Z06 Sold
AKA** Illenema

Last edited by Kb7tif; 03-14-2012 at 11:32 AM.
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Old 03-14-2012   #9
mike100
 
Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
Default Re: Dim Dash LCD Speed Display

Is it the backlight? try turning on your headlamps and adjusting the dimmer lever to maximum brightness.

seems like my 95 LT1 car dimmer function used to work all the time regardless of headlamp function, but the early ones need the lamps on for the dimmer to adjust. they even made the gauge ink white instead of dark yellow on the 94-up cars...obviously these were a little challenging to see even new.
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Old 03-14-2012   #10
Paul Workman
 
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Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
Default Re: Dim Dash LCD Speed Display

If stepping on the brake causes change in the luminance, "grounding" is the first thing that comes to mind. The FSM should help. But, in the mean time, the two circuit ground reference points are on the back of the block at the edge of the bell housing, each right/left bolt is about 6 inches either side of top-center of the periphery. There are 4 lugs on one bolt, and 5 lugs on the other.

As for the connectors on the instrument cluster, there are two; the main one at the corner of the board, and the other is at the top, which serves the LCD pannel. Both connectors can be and should be replaced, if there is any sign of "frosting" (whiteish oxidation) on the pins. (I ran across those connectors a few times when I was searching for parts for the board. I'll see if I can dig them up again.)

P.
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