Engine cooling fans only work when AC is on.

[JRP]

First and foremost, thank you 3Q Jay for the vacuum diagram, it was the one I needed.This question pertains to the cooling fans, is there a certain sensor they work off of? When the engine is idling the fans will not work even when the temp. gauge is reading above normal working temp, but as soon as I turn on the AC they begin to work.Is this a common problem with the "95" Altima? Come to think of it, they weren't working properly since before I changed the motor.Thanks for any and all feedback.

What is the difference between the coolant temp. sensor and the temp. switch? Are they both linked to the cooling fans? Also, what is the electric fan thermostat's function?Thanks for any and all feedback.
Modified by JRP at 6:41 PM 9/17/2009

[3Q Jay]

the cooling fans should always come on with a/c.there is also a thermostatic sensor. measured with consult(like) device, thermostatic sensor/switch will turn on the fans at 203F, and off again at 194F.there is also a relay for the fans, but it might be common to both the thermostatic switch and the A/C signal.

are you sure you are getting up to 203F (mine certainly do if idling in park for a while).