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87 LCD Instrument Cluster

N

nickjgj

Guest
Hello,

I am back. I posted a help message about this before and Ken answered but his suggestion did not work I was hoping that I could get some other ideas.
The problem I am having is that I can't read anything on the cluster.Ken suggested that some of the Halogen bulbs may be blown. Anyway I took the bezel off the instument cluster and all 4 bulbs are lit. It is not an overall dimness problem the problem is the contrast the whole cluster lights up brightly but the actual digits in the digital readouts and the bars in the bargraphs are too dim to see well also the speedometer digital readout works but the bargraph does not and the tach does not seem to work at all
also there is a capital D with a circle around on the tach (for drive?) that is always lit wether the car is in park reverse drive etc. If anyone has an answer to this I will be eternely gratefull as I am running out of hair to pull out.
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
I forgot to mention the cluster Photo Light Cell. That may contribute to the dimness. Try using a flashlight to see if the lights get brighter when you shine it on the photo cell and dimmer when you take it away.

Do the high beam indicator lights and turn signals glow when the display is dim/dark? If so it could be a bad ground.

Also, I seem to remember reading somewhere about the possibility of the LCD display being damaged easily. That would cause you not to have ANY bars showing though in the area that is damaged though. In that case, they wouldn't just be dim, they'd be dead. ;)

Good luck again.

_ken :w
 
J

jnsampson

Guest
Cluster Issues

I've experienced the following problem. Both directional indicators and the bright headlight indicator light and stay lit for a while. In this "mode", the lights for the LCD dash go out, the instrumentation works and in the right light, you can barely read the dash and see that the instruments are working I've tried the fix of running a new ground from the ambient light sensor override to the metal fittings in the door post. It didn't work.

The local Chevy dealer in Aurora CO has diagnosed the problem as a bad capacitor on the circuit board. Does anyone know of a reasonably priced fix for this other than having the entire cluster removed and serviced? It seems that there ought to be a way to just replace the offending circuit board.
 

Top

Well-known member
Joined
Mar 20, 2002
Messages
161
Location
Las Vegas, Nv
Corvette
1986 Convertible Dark Red Metallic
Did you ground both ground wires? D1 and D3 in the 32 way connector. D1 goes to the driver's door pillar. D3 goes to the ambient over-ride sensor under the left dash. According to Gordon Killebrew's Digital Dash book if the high beam and directionals come on you have a bad ground. I did. What I did was cut both grounds as far down the connector as possible. I then soldered them together and ran a new, fresh ground to the door piller post. Haven't had a problen since then.

Good Luck :beer
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Bzzzzttttt

WRONGO!

$150.00 you pay the freight..I'll fix it!


Vig!
 
J

jnsampson

Guest
85 Dash Cluster

Top:

I'll have to check with my mechanic. I didn't do the work myself. I've read Gordon's article in one of the vette mags. However, I don't have the book itself. Guess it would be worth getting it. If you have the information that can be emailed to me as an attachment (MS Word), I'd appreciate it.

thanks,

John Sampson
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
Nick, the dash ground is on the 153 circuit. This is a black/white striped wire in cavity D3 of the large connector to the cluster. The wire goes to an ambient over-ride sensor, then to the bulkhead connector to cavity B1 to the engine harness wire to the left rear of the engine.

The ambient over-ride sensor is located under the dash on the backside of the bulkhead connector on a plastic cover over the wires entering the connector. It is about the size of a dime and 1/2-inch thick with two terminals. One is the 153 circuit, the other returns to the cluster to cavity D7. This is a 911 circuit, dark blue wire. The pupose of the ambient temperature over-ride sensor is when the temperature drops low in the northern areas the LCD will still illuminate.

Ground the 153 circuit at the over-ride sensor. If it works or doesn't work just leave it grounded. If the ground is good and the dash is still inoperative, the cluster may have to be removed and the board terminals cleaned.

_ken
 

Top

Well-known member
Joined
Mar 20, 2002
Messages
161
Location
Las Vegas, Nv
Corvette
1986 Convertible Dark Red Metallic
John,

Ken basically quoted the rest of the page in Gordon's book. It is a great book to have and a must for your library in my opinion.

Lots of good info and you will need it sooner or later to trouble shoot something.

Good Luck! :bu
 
J

jnsampson

Guest
85 Cluster

Vigman,

Are you implying that if I send you the cluster, you'll fix it for $150.00, if I pay the freight?

Top,

Thanks for the info.

:)
 

billd

Well-known member
Joined
Dec 9, 2001
Messages
88
Location
Denver,CO
Corvette
2001 red convertible, 1985 wht
send it to Vig

I went to Corvettes only and also checked into other ways to service the thing. If you dont want to find/ replace the bad parts yourself SENT IT TO VIG. It wont take long
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Sorry

Yes I can fix it.
Sorry it took so long to get back ( REALLY BUSY @ WORK)

I have ALL the stuff ( Test gear ) to fix it @ Home.

Made a FULL CAR EMULATOR.. WITH CRUISE!


So It's pretty easy.... IF you have all the stuff.

Ship it & your cruise servo..I'll test em both!


And will advise a cost BEFORE I start.

Regular bulbs are part of the deal..halogens are extra.

The ONLY part I'm short of is the regulated supply ( +5 )

BUT if you can see the gauges working.. and you have no backlight..it's easy.


Vig!
 
N

nickjgj

Guest
87 LCD instument cluster

Just wanted to post a thank you for all the answers I got from everyone I will let you all know what happens if I ever get it fixed
 

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