A/C Programmer -J127-
WARNING: This page is about a different car, the 2011 Volkswagen CC, 2010 Volkswagen CC, and 2009 Volkswagen CC. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
This programmer switches the refrigerant flow direction through the 2nd evaporator if the temperature on the cooling fins on the 2nd evaporator lowers to the freezing point for water (icing protection).