Nissan Repair: Fan motor, nissan bluebird, radiator fans

Question
I recently bought a Nissan Bluebird ARX EU13. I recently found out that my radiator fans aren't operational. My questions are withthis Nissan model:
1. Are my rad fan motors suppose to come on as soon as the ignition is on?
2. Is there a sensor that tells the motors to come in as soon as a certain temp is reached?
3. Is one of the fans dedicated to the Air conditioning and if so when does it come in?
4. I have done some checks and found out that as soon as the ignition is on 12V is present at the motor plugs at any time.

Please assist where you can.

Answer
Matt,

No, the fans do not come on at startup.  The first comes on when the engine gets hot enough to warrant cooling.  The second one will come on if the car gets really hot and when the airconditioner is on.  The fan temperature switch, relay, fan or fuse is the problem.  I would hotwire the fans to make sure they are not burnt out.  You say you had power at the fan and what normally happens is the relay grounds the fan and it comes on.  If the relay is defective no fan.  So, on the other wire ground it and see if you have a fan.  If so, check the relay and if the relay is good check the fuse and the temperature switch.  The give away for me is that they never come on and that would mean a bad relay, usually...