ETR or Evaporator Temperature Regulator Switch Cycles A/C compressor on and off to prevent the evaporator from "icing" up.
The 1992-1994 version of this switch (VW part # 191 959 281) has been discontinued by VW and is no longer available.
While this switch is designed for 1995-2005 models, it can be used for the early 1992-1994 Eurovans, as well. There are
only two small spade type electrical contacts used.