[s-cars] Auxilliary Air Regulator -- 1981 VW Vanagon

[b1biker at aol.com]

I have a bad auxiliary air regulator on my 81 VW Vanagon, 2.0 air cooled. VW says that it 
is no longer available and I can't find an on-line source. This is a 2-wire 
regulator and I've been told that any 2-wire unit will work. Does anyone know 
of  other VW or Audi models that use a 2-wire auxiliary air regulator so that I can substitute. 
Any assistance will be greatly appreciated.
Gary Meier