If you follow the red, blue, and 2 gray wires from the radio to the area
above the glovebox you may find the answer. There you should expect to
see a connector with those 4 wires going in but only 3 coming out and
just 1 of them gray. This is where the rear speaker grounds join. From
there the 3 wires go up inside the pillar at the corner of the
windshield and are very difficult to follow. If you see 4 wires with 2
grays going up the pillar then you may be in luck. Not likely on an 87.

Mark

Tim Beidel wrote:
>
> Can anyone with experience in installing a new stereo to a 1987 Vanagon
> provide a definitive answer about whether the rear speakers that year shared
> a common ground?
>
> I have 4 wires coming from the rear; they are colored as described in
> Bentley 97.176. That diagram suggests to me that they do *not* share a
> common ground.
>
> I have seen one message in the archives that says they do not, and that
> installation of a modern radio will go fine. There is another message that
> says the ground is melded somewhere in the back and that you should not be
> fooled by the presence of two wires. I've received a private email warning
> the same thing.
>
> Others have said I should use a VOM to check for myself. If I had a VOM (a
> voltage ohm meter?), what should I look for? How do I use one to test these
> wires? (I am sure I can borrow one from somebody).
>
> Thanks,
>
> Tim Beidel
> South Portland, ME
> 1987 Syncro Westfalia