Please can anyone suggest why the Heater Blower on my '98 A4 Tdi 110 Auto should work intermittantly ? HVAC panel responds to buttons, A/C compressor cuts in and out, Fan speed Bar indicator operates but no blow ! Fuse checks out ok. This first happened a few weeks ago, malfunctioned for 3 days then was ok - until today. Could there be a sensor that is inhibiting the Blower ? Lots of questions ...... Robert.