THe ISVCU is part of the ECU.  In other words built in
to the ECU.   Good luck trying to use it.
                                              Eric

Richard Golen wrote:

> Hi All,
>
> I decided to take a closer look at the ISVs in my 87 and my wife's 90
> cabrio. BOTH are two wire units. So that was a plus.....
>
> My next step was to swab ISV control units. I found the Vanagon's ISVCU
> cleverly hidden behind the right tail light housing....however after
> searching for about 20 minutes, the ISVCU in the Cabriolet remains elusive....
>
> At least the 2 v 3 wire-vanagon-vs-cabrio mystery has been solved. If
> anyone knows where VW has hidden the ISVCU on the 90 Cabriolet, perhaps I
> can solve the rest of the mystery!
>
> Ric