[V8] Intermittant IC ground and Oil Pressure warning light fi xed!

[Buchholz, Steven]

Great work Ingo!  Thanks for passing along what you've learned!

... I've managed to collect a couple spares over the past couple years ...
and there's the real 5-speed unit I have with the cracked bezel ... I can
get a feeling for how common an issue this is ... and perhaps give the other
circuit boards a bit more scrutiny ...

Steve B
San Jose, CA (USA)
> 
> OK.  I finally figured out what was causing my IC problem.  
> First let me
> explain what enabled me to finally figure it out.  I have been driving
> without my dash pad for the past few weeks.  When the ground 
> for the Water
> temp and fuel gauges would disappear I found that often by 
> pushing forward
> the top of the IC while driving contact would be 
> restored...for a while.
> Sometimes this didn't work and I found that fiddling with the 
> loom at the
> back of the IC attached to the yellow plug, the contact would also be
> restored -- but I still had the aggravating oil pressure 
> warning display and
> chime come on intermittently.  So last evening I once again 
> removed the IC
> and took off the main back panel containing the boards for 
> the computer
> warning display and then proceeded to remove both circuit 
> boards.  When
> laying on the workbench (or in my case kitchen table) and 
> with the warning
> display at the top, I first removed the screws attaching the 
> right side
> circuit board, as that one plugs into the left side (see green plug on
> left -- this turns out to be the critical area).  I used 
> Deoxit to clean the
> pin contacts there and the long strip of contacts in the 
> middle of the right
> circuit board.  Then I reassembled and reinstalled in the 
> car.  Drats, the
> low oil warning light came on almost immediately.  It was 
> late and I decided
> to bag it.
> 
> This morning I made an interesting discovery:  Two pins from 
> the IC were
> laying together in my work area from the night before!  Hmm, 
> out goes the IC
> and I disassembled once more to find that the missing pins 
> belonged to the
> left circuit board where the right circuit board plugs into 
> the left one and
> with a third pin about to fall out!  I think there are eight 
> pins in total.
> So I removed the left circuit board and resoldered all of 
> these pins... the
> solder joints were all suspect.  Reassembled and Voila!  No 
> more warnings
> and I believe this will definitely take care of the problem.  
> Now all my
> previous experiences made sense.  Bad solder joints on these pins.  So
> before I replaced the board, I press-fitted the two boards 
> together to make
> sure the pins were securely soldered in and then screwed them 
> back into the
> white plastic back of the board.  Don't forget to plug the 
> warning chime
> into the plug on the right of the board.  I would have taken 
> pics, but I
> left both digicams at the office yesterday!