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RE: Quattro speedo
I think that the 200 models after '88 years have a slightly different
connectivity than the pre-1988, in the ciruit board layout. There was a
post which included a web link to a TSB: www.geocities.com/MotorCity/5614
I expect there are more similarities in the problems that can occur, only
that the failure point in the instrument cluster may be different.
On mine, there were four pins which connected the Speedo Guage to the
instrument cluster circuit board. Where each of these these pins were
soldered into the circuit board on the speedo gauge board resembled a cold
solder joint(probably due to age/thermal cycling and stress).
My guess would be the problem could be at either these pins - I suspect they
still used this type of connection to the speedo guage after '88, or the
solder point described in the TSB - definately a probable culprit.
It wouldn't hurt to perform tests described in the Bently Manual first, as
that would isolate the problem to the car wiring (including the instrument
cluster), or a failed sending unit (not likely). These tests can be
performed with a VOM.
Regarding outside temp effecting operation, I postulate that if it is cold,
the circuit connections are more likely to not be making contact due to
contraction of the components.
Mine worked beifly as I was bringing the car to the inspection station.
then it failed, and I had to fix it to get the car through inspection.
I performed Bently tests which suggested car wiring - as assumed they ment
"including instrument cluster" especially since I didn't want to tear the
Anyway, a light bulb went off to swap units in my two cars '86 & '87 CSQTs.
When I did, the working speedo worked fine in the '86 - duh. The on NOT
WORKING AT ALL in the '86 went to BOUNCING when I put it in the '87. I
suspect this is because moving the units around allowed the contacts to make
slightly. But this allowed me to isolate to the instrument cluster which I
spent days trouble shooting, until Alan C. pointed me to the actual problem
in the speedo guage itself.
I'm sure you'll find the obvious problem after days of troubleshooting too.
**Anyone else who knows the difference between the 5000 and 200 TQ speedos/
circuit board setup, please chime in.
'85 4KSQ - For sale, still registered, can drive away if anyone interested.
Needs - F.Struts, CV Boot, Shift linkage fix, exhaust. Misc. other and
cosmetic. Engine is strong!
From: tubman [mailto:email@example.com]
Sent: Sunday, September 05, 1999 1:47 AM
Subject: Quattro speedo
I saw your post on the quattro-digest about speedo repair.
The speedo in my 90 200 TQ behaves similarly, but only when
it is cool/cold outside. (I live in Alaska, so that is most
of the time.) I had been assuming it was the sender,
especially since the behavior is sensitive to the outside
temp. Did your also display this behavior, or was it all