The 80-84 have a similar weakness but even worse.

They have 2 brown wires coming from 2 pins on the 14 pin connector.
For these, cut both browns leaving a just few inches hanging from the
connector. Twist those together and extend them with another piece of
wire. Put a ring on the end and screw it to bare metal nearby. This is
the new ground for the cluster 14 pin.

The 2 long brown cut ends running down into the dashboard wiring need to
be connected together so some things down the line will still work.

Mark

Jim Felder wrote:
> 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
>>
>>