[85 LCD] The Dreaded Intermittent Electrical Problem
Thread Starter
Le Mans Master
Joined: May 2003
Posts: 8,175
Likes: 237
From: Philadelphia Burbs
Cruise-In V Veteran
St. Jude Donor '06
[85 LCD] The Dreaded Intermittent Electrical Problem
Sometimes, either when I've just started up or I've been driving for a couple of minutes, the LCD display on my 1985 will go completely blank. Everything else (at least everything else I've had the presence of mind to check while this is happening) keeps working fine. Sometimes the LCD display will give the impression that something is going on, but most of the time it is completely blank.
A couple of restarts later, the LCD display will magically start working again.
I looked in the 1985 service manual (I'm learning
) and the #1 troubleshooting hint for the instrument cluster is to check the LCD fuse, the CLSR fuse, and the G201 ground.
Some questions:
1) I'm assuming that it can't be the fuses since the LCD display works most of the time. Is that correct?
2) The G201 ground is said to be behind the instrument panel and near the left hand side of the steering column. I looked through the entire electrical diagnosis portion of the service manual and I can't for the life of me find a diagram that shows the location [there are diagrams that show G100, G101, G103, G104, G115, G116, G125, G140, G320, G400, and G401
]. Is G201 hard to get to?
3) Am I missing something really obvious?
A couple of restarts later, the LCD display will magically start working again.
I looked in the 1985 service manual (I'm learning
) and the #1 troubleshooting hint for the instrument cluster is to check the LCD fuse, the CLSR fuse, and the G201 ground.Some questions:
1) I'm assuming that it can't be the fuses since the LCD display works most of the time. Is that correct?
2) The G201 ground is said to be behind the instrument panel and near the left hand side of the steering column. I looked through the entire electrical diagnosis portion of the service manual and I can't for the life of me find a diagram that shows the location [there are diagrams that show G100, G101, G103, G104, G115, G116, G125, G140, G320, G400, and G401
]. Is G201 hard to get to?3) Am I missing something really obvious?
Last edited by j3studio; Aug 17, 2004 at 05:41 PM.
Racer
Joined: Feb 2002
Posts: 293
Likes: 0
From: Benoni Gauteng
I would check the fuse anyway, quick and easy. Maybe you should try checking the connectors on the display itself. this is not such a great job as you have to remove the whole display cluster. It has 2 connectors on the left at the back
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Hey I've got an 85 that has the exact same symptons you describe... only problem is, about 3 or 4 days ago, it went black, and hasn't come back since... Maybe we could help each other on this... I've tried a ton of stuff trying to fix it... i haven't heard of the ground near the steering column though. I've checked (and cleaned) 3 other grounds related to this, and it hasn't helped. Have you search for this ground yet?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
ah... that could be interesting... on TOP of the steering column, there are a multitude of wires connecting to the ignition system, signals and such. you may have to drop the column from the dash to reach them ok. A corroded connection could cause this problem.
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Instructor
Joined: Jul 2000
Posts: 203
Likes: 3
From: Galesburg IL
I agree that it sounds like a ground problem. This site has some good information on the digi dash. www.batee.com/corvette/index.shtml
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by steveb
I agree that it sounds like a ground problem. This site has some good information on the digi dash. www.batee.com/corvette/index.shtml
Hey j3studio, have you tried anything yet to solve your problem? I'm interested to see if you've done anything i haven't
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
G201 should be on the left kick panel. Remove the hush panel and then find the black support bar. It's either on it or next to it.
Doubt that's your problem though. This ground is spliced to a host of other stuff, so if everything else is working ok, this ground is probably good.
The other ground could be your problem. It runs to the ambient temperature overide switch and then out through the big connector behind the battery to the trans (upper left bolt for your year). As Killebrew points out, that connector can collect water in the base, where the ground passes through, corroding the contacts. His solution is to solder the grounds at the display - pins D1 & D3.
If you're going to remove the connector, take out the battery first. The upper half is the light circuits - all the engine stuff is in the bottom. Cleaning it can be a chore and some electrical cleaner that won't harm the plastic works pretty well. Smear dielectric all over everything and then Killebrew recommends that you spray it with undercoating after it's back together. Do make sure that the fresh air plenum drain tube is pointing away from it and the fusible links behind the battery.
Doubt that's your problem though. This ground is spliced to a host of other stuff, so if everything else is working ok, this ground is probably good.
The other ground could be your problem. It runs to the ambient temperature overide switch and then out through the big connector behind the battery to the trans (upper left bolt for your year). As Killebrew points out, that connector can collect water in the base, where the ground passes through, corroding the contacts. His solution is to solder the grounds at the display - pins D1 & D3.
If you're going to remove the connector, take out the battery first. The upper half is the light circuits - all the engine stuff is in the bottom. Cleaning it can be a chore and some electrical cleaner that won't harm the plastic works pretty well. Smear dielectric all over everything and then Killebrew recommends that you spray it with undercoating after it's back together. Do make sure that the fresh air plenum drain tube is pointing away from it and the fusible links behind the battery.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by SunCr
The other ground could be your problem. It runs to the ambient temperature overide switch and then out through the big connector behind the battery to the trans (upper left bolt for your year). As Killebrew points out, that connector can collect water in the base, where the ground passes through, corroding the contacts. His solution is to solder the grounds at the display - pins D1 & D3.
Burning Brakes
Joined: Jan 2003
Posts: 931
Likes: 3
From: Portland OR
This right here did it for me. Once I soldered this extra ground on my 86 all my worries went away.
$200? Nope. Just replaced the bulbs and added one piece of wire.
Here's the page.
It might look complicated to some but it was relatively easy. Just keep unscrewing the IP until you get to the good stuff. I got so good I could get the IP out in my sleep. (Kept taking it out until I found out how to fix it, finally).
Nothing feels better than after putting up with an intermittent dash to know that it'll never flicker again.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by yellowlust
This right here did it for me. Once I soldered this extra ground on my 86 all my worries went away.
$200? Nope. Just replaced the bulbs and added one piece of wire.
Here's the page.
It might look complicated to some but it was relatively easy. Just keep unscrewing the IP until you get to the good stuff. I got so good I could get the IP out in my sleep. (Kept taking it out until I found out how to fix it, finally).
Nothing feels better than after putting up with an intermittent dash to know that it'll never flicker again.
Burning Brakes
Joined: Jan 2003
Posts: 931
Likes: 3
From: Portland OR
Originally Posted by mikey whipreck
That looks good, and if j3studio hasnt tried it yet he definitely should. But I seem to be having the same symptons his dash has, and I HAVE done that... and it didn't help
Thread Starter
Le Mans Master
Joined: May 2003
Posts: 8,175
Likes: 237
From: Philadelphia Burbs
Cruise-In V Veteran
St. Jude Donor '06
Re: The Dreaded Intermittent Electrical Problem
Originally Posted by mikey whipreck
Hey I've got an 85 that has the exact same symptons you describe... only problem is, about 3 or 4 days ago, it went black, and hasn't come back since... Maybe we could help each other on this... I've tried a ton of stuff trying to fix it... i haven't heard of the ground near the steering column though. I've checked (and cleaned) 3 other grounds related to this, and it hasn't helped. Have you search for this ground yet?
I haven't gotten to this yet - the engine is throwing codes again
, so that's my biggest priority right now. I don't have Gordon's digital dash book, though that's probably going to be a Carlisle pick-up.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by yellowlust
Have you also addressed the ambient temperature switch ground?
Thanks for the input guys... I ordered Killebrew's book a few days ago, and i'll try it again when I get it... I also plan on being at Carlisle, maybe i can get some more input from people that have been through digital dash hell
