These are commonly available from FWD VW aftermarket suppliers for
about $25 each have been available for years, Rapid Parts and
WolfSport come to mind, call around to people in European Car mag.
The relay in fact fits numerous european cars.  I have one that has
resided in '89 Jetta, '86 Quantum, '90 Passat, '90 Corrado, and now
the '85 Van in that order, have meant to try it in the '78 but never
have gotten around to it.

John