1985 Dash Lights out - CorvetteForum - Chevrolet Corvette Forum Discussion


C4 Tech/Performance
L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1985 Dash Lights out

Reply
 
 
 
Thread Tools Search this Thread
Old 03-11-2017, 11:10 AM   #1
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default 1985 Dash Lights out

The dash lights on my 85 are out. I read in This thread that a blown tail light can do this. I do have a blown tail light, but I find that hard to believe. I see that the tail light FUSE could be part of the problem, but would a single tail light do this too?

Note: I've tried two different gauge clusters, I was told at least one of them was working, but haven't actually confirmed that myself. While it's completely possible both clusters were bad, I'm also seriously questioning if there is something else going on before I buy an expensive cluster.
Bfenty is offline   Reply With Quote
Old 03-11-2017, 11:42 AM   #2
billschroeder5842
ZenVette Master level VII
Support Corvetteforum!
 
billschroeder5842's Avatar
 
Member Since: Mar 2016
Location: Southlake, TX
Posts: 2,184
Thanked 239 Times in 214 Posts
Default

Yes, if you have a "blown" tail light you probably have grounding issues. Electricity will take the path of least resistance to ground itself out and often it is through your dash/cluster.


So, fix your known problem and change out your fuse.


Your (soon to be purchased??) shop manual will have clear wiring diagrams so you will be able to trace your electricity flow easily.
billschroeder5842 is online now   Reply With Quote
The Following User Says Thank You to billschroeder5842 For This Useful Post:
Bfenty (03-11-2017)
Old 03-11-2017, 11:48 AM   #3
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

Quote:
Originally Posted by billschroeder5842 View Post
Yes, if you have a "blown" tail light you probably have grounding issues. Electricity will take the path of least resistance to ground itself out and often it is through your dash/cluster.


So, fix your known problem and change out your fuse.


Your (soon to be purchased??) shop manual will have clear wiring diagrams so you will be able to trace your electricity flow easily.
The gauge fuse isn't blown-or is that not the fuse you mean?

I'm buying the shop manual now so I don't have to ask stupid questions lol. CD Rom is cheaper, are they in pdf format on the cd usually so I could just print it out from there? Or some stupid proprietary format?

EDIT: I was able to read the fine print on the back of the cd in the ebay listing-it's in PDF! I will probably go that route.

Last edited by Bfenty; 03-11-2017 at 11:49 AM. Reason: more info
Bfenty is offline   Reply With Quote
Old 03-11-2017, 12:00 PM   #4
billschroeder5842
ZenVette Master level VII
Support Corvetteforum!
 
billschroeder5842's Avatar
 
Member Since: Mar 2016
Location: Southlake, TX
Posts: 2,184
Thanked 239 Times in 214 Posts
Default

Not sure on your year but (if you have) your owners manual it will have a simple diagram of your fuse box.


There probably is a fuse for your rear tail light section as there is a LOT going on back there- brakes, running lights, turn signals....etc.


BTW... buy the book. It will be easier to set the manual on your front tire and flip pages while you spin your wrench than to scroll up and down while trying to balance your lap top on your knee.


Old school technology rocks.
billschroeder5842 is online now   Reply With Quote
The Following User Says Thank You to billschroeder5842 For This Useful Post:
Bfenty (03-11-2017)
Old 03-11-2017, 06:59 PM   #5
VikingTrad3r
CF Senior Member
Support Corvetteforum!
 
VikingTrad3r's Avatar
 
Member Since: Apr 2014
Posts: 3,686
Thanked 268 Times in 252 Posts
Default

fenty, if you want to get started cleaning and confirming your grounding locations are all in top notch order, you can Google 1985 Corvette ground locations, and I think you will find a diagram. Off the top of my head I know there is one on the rear of the driver side head it is quite a little rats nest of cables, to get a very good view point on it you could remove, temporarily, the wiper motor but this is not absolutely necessary.
The other location is on the driver side of the bell housing up near the top.

there are more locations to be sure as per a diagram that you find, but these two I can recall from memory when I rebuilt my 85.

getting these cars running in as new condition is a rewarding challenge, and much of it is trial and error. You are on the right track when trying to diagnose something as opposed to parts swapping, the amount of money required to get the cars running as new is high enough without all the extra part swapping.
VikingTrad3r is offline   Reply With Quote
The Following User Says Thank You to VikingTrad3r For This Useful Post:
Bfenty (03-11-2017)
Old 03-11-2017, 07:39 PM   #6
rharker
CF Senior Member
 
rharker's Avatar
 
Member Since: Nov 2007
Location: Gainesville FL
Posts: 907
Thanked 20 Times in 18 Posts
Default Maybe your digital dash needs repair

Can you see the LCD elements when you shine a flashlight at the digital display? If so then you may have burned out lamps. If not you may have a bad power supply.

I just went through fixing my digital dash replacing faded polarizing film and changing the lamps for cooler running xenon bulbs. You can even find colored LED lamps.

You can find troubleshooting guide on youtube here:


About the FSM PDF CD if you go that route make sure the PDF file is indexed instead of one giant image file. You can't search the later for keywords or click on specific chapters.
rharker is offline   Reply With Quote
The Following User Says Thank You to rharker For This Useful Post:
Bfenty (03-11-2017)
Old 03-12-2017, 01:14 PM   #7
FrostyMountain
CF Member
 
Member Since: Oct 2016
Location: Cleveland Tennessee
Posts: 54
Thanked 2 Times in 2 Posts
Default

I agree with those who say get the book, not CD. i have a CD not searchable, have ordered a manual. If you want my CD PM me with a mailing address and Ill send you mine free
FrostyMountain is offline   Reply With Quote
The Following User Says Thank You to FrostyMountain For This Useful Post:
Bfenty (03-12-2017)
Old 03-12-2017, 01:30 PM   #8
bxtech
CF Senior Member
 
bxtech's Avatar
 
Member Since: Nov 2011
Posts: 128
Thanked 11 Times in 9 Posts
Default

Quick and dirty way to check the ground to the cluster: Remove the metal access cover for one of the instrument cluster Halogen bulbs. Run a small wire (like 16ga) from ground, and touch the ground side of the bulb of which you removed the access plate. The cluster should light up and verifies that you have a ground issue. I've done this test on two cars I've owned in the past, and both had the same issue.
bxtech is offline   Reply With Quote
The Following 3 Users Say Thank You to bxtech For This Useful Post:
Bfenty (03-12-2017), rharker (03-12-2017), teal9550 (03-18-2017)
Old 03-12-2017, 07:46 PM   #9
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

Quote:
Originally Posted by bxtech View Post
Quick and dirty way to check the ground to the cluster: Remove the metal access cover for one of the instrument cluster Halogen bulbs. Run a small wire (like 16ga) from ground, and touch the ground side of the bulb of which you removed the access plate. The cluster should light up and verifies that you have a ground issue. I've done this test on two cars I've owned in the past, and both had the same issue.
That sounds like an excellent method-I will try that!
Bfenty is offline   Reply With Quote
Old 03-13-2017, 02:35 AM   #10
Cliff Harris
CF Senior Member
 
Cliff Harris's Avatar
 
Member Since: Apr 2002
Location: Anaheim CA
Posts: 10,017
Thanks: 0
Thanked 293 Times in 273 Posts
Default

It is very common for the connectors between the dash PC boards to have crystallized (broken) solder connections. The ones to look at are on opposite ends of the connectors (+12 volts and ground). A poor connection will cause the area around the pins to turn black (burned by poor connection that gets hot).
Cliff Harris is offline   Reply With Quote
The Following User Says Thank You to Cliff Harris For This Useful Post:
Bfenty (03-13-2017)
Old 03-13-2017, 09:17 AM   #11
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

Quote:
Originally Posted by Cliff Harris View Post
It is very common for the connectors between the dash PC boards to have crystallized (broken) solder connections. The ones to look at are on opposite ends of the connectors (+12 volts and ground). A poor connection will cause the area around the pins to turn black (burned by poor connection that gets hot).
This weekend I think I'm going to pull the dash out and bench test it. I have a 12v power supply I can hook it up to for power and test connections. I'm pretty handy with a soldering iron so I'm optimistic I can fix it if the problem is as you describe.
Bfenty is offline   Reply With Quote
Old 03-13-2017, 10:24 AM   #12
rharker
CF Senior Member
 
rharker's Avatar
 
Member Since: Nov 2007
Location: Gainesville FL
Posts: 907
Thanked 20 Times in 18 Posts
Default

@Bfenty -- You might take the opportunity to replace the polarizing film. I wouldn't say that it is an easy job just tedious. Changing the bulbs is easy.
rharker is offline   Reply With Quote
The Following User Says Thank You to rharker For This Useful Post:
Bfenty (03-13-2017)
Old 03-14-2017, 12:56 AM   #13
xrav22
CF Senior Member
 
xrav22's Avatar
 
Member Since: Mar 2013
Location: Canoga Park Cali.
Posts: 1,010
Thanked 85 Times in 81 Posts
Default


Add to this the one I found at the end of my taillight harness near the antennae.
My lights did not work and I had to totally rewire them
Good luck
xrav22 is online now   Reply With Quote
The Following User Says Thank You to xrav22 For This Useful Post:
Bfenty (03-14-2017)
Old 03-14-2017, 08:38 AM   #14
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

That's a good list to start with-thanks!
Bfenty is offline   Reply With Quote
Old 03-18-2017, 09:32 PM   #15
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default


well, I have bench-tested the dash, and it works! So it's something in the car that's the issue. I think something is wrong with the LCD fuse (which the gauges won't come on without...right?). I looked behind the fuse box and there are two red wires coming out one side of it and nothing out the other side, like a wire came loose or something. I can't find one down in the dash anywhere behind the fuse box though.
You can see the two red wires going straight into one side of the same fuse here

Last edited by Bfenty; 03-18-2017 at 09:57 PM. Reason: adding photo
Bfenty is offline   Reply With Quote
Old 03-18-2017, 09:53 PM   #16
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

also, the FSM says to refer to section 8A for diagnosing the dash electrical issues-but I can't find a section 8A! It goes straight to 8B...
Bfenty is offline   Reply With Quote
Old 03-18-2017, 09:55 PM   #17
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

Quote:
Originally Posted by bxtech View Post
Quick and dirty way to check the ground to the cluster: Remove the metal access cover for one of the instrument cluster Halogen bulbs. Run a small wire (like 16ga) from ground, and touch the ground side of the bulb of which you removed the access plate. The cluster should light up and verifies that you have a ground issue. I've done this test on two cars I've owned in the past, and both had the same issue.
Which side is the ground side of the light? Is there an easy way to tell?
Bfenty is offline   Reply With Quote
Old 03-18-2017, 11:04 PM   #18
xrav22
CF Senior Member
 
xrav22's Avatar
 
Member Since: Mar 2013
Location: Canoga Park Cali.
Posts: 1,010
Thanked 85 Times in 81 Posts
Default


Mabey this helps I believe it is the large connector. I remember spraying electrical cleaner on the pins and inside the plug because it was very dirty.

Last edited by xrav22; 03-18-2017 at 11:05 PM.
xrav22 is online now   Reply With Quote
The Following User Says Thank You to xrav22 For This Useful Post:
Bfenty (03-19-2017)
Old 03-18-2017, 11:20 PM   #19
TBSS/85vette
CF Senior Member
 
TBSS/85vette's Avatar
 
Member Since: Dec 2012
Location: Rockford Illinois
Posts: 281
Thanked 7 Times in 7 Posts
Default

Quote:
Originally Posted by xrav22 View Post

Add to this the one I found at the end of my taillight harness near the antennae.
My lights did not work and I had to totally rewire them
Good luck
If you're having trouble with the turn signals and lights there is a connector at the base of the steering column. Check that there are no loose pins in it. That was where the problem was in my 1985. I wasted my time checking on the grounds.
TBSS/85vette is offline   Reply With Quote
The Following User Says Thank You to TBSS/85vette For This Useful Post:
Bfenty (03-19-2017)
Old 03-19-2017, 12:48 AM   #20
Bfenty
CF Senior Member
C4 of the Month Finalist 2017
Thread Starter
 
Bfenty's Avatar
 
Member Since: Mar 2017
Location: Nashville TN
Posts: 736
Thanked 33 Times in 31 Posts
Default

ok cool. I'll check that out. It's good to know it's not the dash panel at least.
Bfenty is offline   Reply With Quote
Go Back   CorvetteForum - Chevrolet Corvette Forum Discussion >
Reload this Page
  • 1985 Dash Lights out
  •  
     
    Reply

    Related Topics
    Thread Thread Starter Forum Replies Last Post
    Strange Short in the Lights Bergerboy C3 General 2 09-26-2017 06:55 PM
    98 c5. No dash lights, tail lights, or fog lights Brandon Cannon C5 Tech 2 02-15-2017 08:30 PM
    Let there be lights! Uh oh.... Quantumleap C4 General Discussion 4 11-18-2016 03:15 AM
    Hit bump, no interior light. Brad_B C3 Tech/Performance 4 05-19-2016 01:47 PM
    NO Tailights The Highlander C5 Tech 6 03-07-2016 06:40 PM


    Thread Tools Search this Thread
    Search this Thread:

    Click for Advanced Search

    Posting Rules
    You may not post new threads
    You may not post replies
    You may not post attachments
    You may not edit your posts

    BB code is On
    Smilies are On
    [IMG] code is On
    HTML code is Off
    Trackbacks are Off
    Pingbacks are Off
    Refbacks are Off

    Forum Jump

    Sponsored Ads
    Vendor Directory

    All times are GMT -4. The time now is 09:55 PM.


    We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
     
    • Ask a Question
      Get answers from community experts
    Question Title:
    Description:
    Your question will be posted in: