Chevrolet Repair: Transaxle control, feedback section, transaxle

Question
2000 Blazer LS 4WD

Hi.  When I push the dash button to switch to "2-HI", the indicator light flashes a few times and then it switches to "4-HI" automatically.  I can also hear some clicking somewhere under the dash while this is happening.  If I push the "AUTO 4WD" button, it switches to that mode ok.  It just won't go into "2-HI".  Someone told me to replace the "transaxle control module", but I don't know where to find it or what it looks like.  Is this the cause and where is it?
Thank you very much!

Answer
Hey,

  Typically its the control servo on the transfer case that goes bad. The clicking you are hearing are the relays or controller trying to actuate the diff.  The lights flash when a mode cannot be selected by the ecu or the feedback section of the motor gives erroneous signals.

Wayne