DuB-EnG: Fan Heater Speed Control repair on Wolkswagen T5 T6 - Resistor matrix repair / replacment

Your fan heater only works on setting 4 (maximum) and the lower speed settings 1, 2 and 3 do nothing. Here is a video on how to replace the wire-wouund speed control resistor matrix and an investigation on how it works and what the cause of the failure is.