Mark, what about the 83s?

Jim

On Sat, Feb 21, 2009 at 10:30 PM, mark drillock <mdrillock@cox.net> wrote:
> VW combined many instrument cluster items to a single ground wire on the
> 14 pin connector. Then they combined that single ground wire with a
> bunch of other dash ground wires all into one final wire which then runs
> to the main ground star. When everything was working fine, say for 15-20
> years, this combined ground system was ok. Now we are past that point.
>
> You likely have a bad ground for the instrument cluster. When a ground
> gets flaky, some of the anxious electrons look for another path to get
> home. Sometimes they try to flow backwards into a wire for something
> else if that looks like their best escape route. That can make other
> things on those escape routes act screwy.
>
> The first simple step is to put the instrument cluster on a dedicated
> ground wire. Just cut the brown wire to pin 3 of the 14 pin connector,
> leaving a few inches. Splice some more wire to the cut end that is now
> hanging from the 14 pin connector. Put a ring end on it. Screw that ring
> down to bare metal in the dash area. Hopefully in a spot where it will
> be noticed if someday in the future someone is checking out another
> problem with the ground. You don't need to do anything with the other
> cut end of the brown wire going down into the dash. Tape it off if it
> makes you feel better but do not attach it to anything.
>
> (pin 3 of the 14 pin connector is only the ground wire for 85-91
> clusters, and the rare 84 tach cluster)
>
> If that step does not solve the problems the biggest thing left is the
> spring pins in the 14 pin connector itself. They can loose their tension
> or get bent from being plugged in and out. If you look closely into the
> open edge at the spring pins you can see if the brown wire's pin has a
> problem. With care and good light you can put a touch more curve in the
> pin so it sticks up into the opening slightly more to make stronger
> contact. This will make the curved edge a tighter fit when it is plugged
> back onto the cluster.
>
> Mark
>
> James Ballen wrote:
>>
>> Hey folks,
>>
>> Hopefully some collective wisdom from the group can help me figure out
>> what's going on with my instrument cluster wiring.
>>
>> I have an '86 wolfsburg weekender that came with an analog clock cluster.
>> PO installed a cluster from an '85 w/a tach.
>> Everything works except a few things:
>>
>> -the coolant temp sensor does not work with the headlight switch turned
>> on.  I had the boys at Buslab fix this about a year ago...Marco told me it
>> was a shorted wire somewhere...and it worked fine until the other day when
>> it started happening again.  Pin #6 on my dash connector (coolant temp
>> sensor) has a wire butt-spliced onto it that goes down to the back, bottom
>> left of the fuse/relay box.  I can't tell exactly what it's plugged into,
>> but I think it's a relay.  Not sure why it's spliced, but it was working
>> fine until a couple days ago.  Temp accuracy was verified with an infared
>> temp gun.
>>
>> -once the coolant system is nearly up to operating temp, the tach sits up
>> around 4k.  Once the engine is revved up to ~1800 the tach then reads
>> accurately.  As soon as it goes back to idle, the needle shoots back up to
>> 4k.  While it's warming up, the needle reads accurately around 900 at idle,
>> but introducing other electrical loads affects the reading.  For example, if
>> I turn on my headlights, the tach needle jumps up a bit, or if I turn on the
>> turn signal, the tach will bounce in time with the blinking.
>>
>> -the coolant LED sometimes flashes a longish amount of time upon startup
>> before going out.  I know the coolant level is good.
>>
>> Things I've done:
>>
>> I acquired another cluster from another '85 van.
>> Symptoms are exactly the same.  This should rule out the cluster being the
>> problem...
>> With my meter, I measured 0 ohms resistance on the pin #3 ground to chasis
>> ground, so the ground should be good...
>> I unhooked pin #12, the dynamic oil buzzer system, since the '85 cluster
>> doesn't have this function, but there is no change in anything.
>>
>> I'm sort of at a loss.  That spliced coolant sensor wire may have
>> something to do with the coolant sensor problem, right?
>>
>> But that still does not explain the tachometer problem.
>> I've read that there is an oil pressure sensor (I think) that starts
>> engaging after 2k RPM, is this right?  Seems like that could be related to
>> the tach issue since they both relate to 1800-2000 RPM...but I don't know
>> anything about it.
>>
>> Any suggestions are very welcome.  Please PM me as I am on digest mode and
>> sometimes don't receive posts until a day or two later.
>> Hopefully I've been specific enough for you to have some ideas...
>>
>> Thanks!
>>
>> /james
>>
>