Audi 200 multifunction woes

[mike posner]

  ----- Original Message ----- 
  From: mike posner 
  To: quattro at audifans.com 
  Sent: Saturday, January 08, 2005 2:33 PM
  Subject: Audi 200 multifunction woes


  I'm in the process of replacing my multi -malfunctioning
  switch for the for the fourth time in 6 years as  my h2o guage
  has gone south again.  I am also unable to get current to
  my ac clutch which has been recently replaced. I have been
  studiously reading the large amount of material on diagnosing  the a/c system and Im, getting lit up on 3, 5 and 7 on channel 7, and channel 3 only on channel 17, but this somtimes has read 3, 5, and 7 as well.. I plan to replace
   the  mfts, but have some concern in that I'm getting 
  3.4 volts off the temp wire (T) as well as 12 volts off the (+) wire which is ok.   Should the T wire (y/brn)  show voltage
  or does this suggest a short from the ac control panel?

  I'm concerned about blowing out a new sensor  by exposing the temp wire to voltage that shouldn't be there. I also rewired the 4 wire plug making sure the right wires were
  going to the right functions, noting that the sensor has
  almost invisably marked T,R,C and + over their respective terminals. 

  TIA  Mike