Hi,
  I have a 1990 Vanagon GL and just recently the knob for the front  heater
stuck in the number 3 position.  It will turn off and back on to  number 3
fan position if I wiggle the knob but will not move back to number 2, 1  or
off position.  Also the knob pulls out of the switch but doesn't look
broken.  Any ideas how to fix this?  I need my heater to work  correctly in these
cold weather days.

Thanks,
David