Re: flaky dash display

[cordeiro@adi.com (Alan Cordeiro)]

The old "flaky" conection problem again, in two co-incidental cases ?

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Hello Folks,

This morning upon startup of my '89 100Q, instead of getting the reassuring
"OK" from the instrument cluster display, all I saw were four horizontal
white lines -- top two closely spaced, bottom two widely spaced.  I cut the
ignition and tried again, with the same result.

It's a cool (45F) morning, and humidity is low;  never saw this behaviour
before, neither at sub-zero temps, nor in high humidity.  Is my computer
getting dislexic. or...?

Any suggestions/war stories from others having seen this greatly appreciated,

Jos
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My '89 200 has a loose connection (I think) somewhere behind the
instrument panel which causes the speedometer gauge to wildly fluctuate
from time to time (actually, it seems correlated to ambient temperature
- it gets worse in cold weather).  I believe it's a mechanical connection
problem since I can "fix" the problem temporarily by tapping on the
instrument panel.

This morning, I also noticed that my radiator temperature gauge is
also misbehaving (it reads cold when it shouldn't and I again was
able to "fix" it by tapping as above).

So it looks like I'll finally have to spend the time to fix this problem in a
more permanent way.  I tried removing the instrument panel once before
(for another problem) but didn't get too far before I found that I didn't
have to.   As I remember, I wasn't having too much success and couldn't
figure out the sequence of operations (which screws to remove and in which
sequence).

Before I embark on this project, I'd like to get some tips from anyone
in the group who's encountered a similar problem, especially on
disassembling the instrument panel and on fixing a possibly loose
connections in this area.

Thanks in advance,

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I had posted a method that had worked well for me when I had encountered
a "flaky" connection in the wiring behing the instrument panel.

First remove the steering wheel. I know that it is POSSIBLE to remove the
instrument panel without this, but it hardly takes five minutes to do.

Next, the LIGHTS,TURN SIGNAL,CRUISE switch assembly comes out. At this point
you can get the instrument panel assembly out.

If you can get hold of a liquid flux used in electronic assembly shops,
it is one of the best for getting the oxide coating off ciruit board 
foils. An easier to get alternative is Radio Shack "TV TUNER/CONTACT 
LUBRICANT", and this works with a bit more elbow grease with a cotton
swab, and paper towel wrapped over the edge of a flat bladed screwdriver.

I have had good luck with a contact LUBRICANT known as "CRAMOLIN OIL"
manufactured by CAIG LABORATORIES. It is usually available at better
electronics parts supply outlets, one example is MCM ELECTRONICS is Ohio.
Spray this oil sparingly over the contact surfaces before re-assembling 
the panel/wiring connectors together.

The " - - - - " display and eratic speedometer seem to point to bad GROUND
connections. If you ( very delicately ) unscrew the  four or five ( ?? ) gold 
color nuts spread over the back of the instrument panel, clean well under
them ( spray a bit of cramolin oil if you have it on hand ) and retighten 
( DO NOT OVERTIGHTEN ), the quality of ground connections will be 
dramatically improved.

The worst connector to clean is the mini-connector that goes into the 
" 8 8 8 8 "  ( or should I say " - - - - " ) trip computer display. It is 
hard to clean inside those female contacts.

Try and purchase a few instrument panel lamps before you embark on this
project, and you can replace the bad ones while you have it off. They are
OSRAM/SYLVANIA 2721MF8, ( Almost sure, not 100%, of the number )  available 
much cheaper from places other than the dealer if you can give them a part 
number. 

Good luck,

Alan Cordeiro
'86 5000 TQ