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Have a st191 caldina with the 3sfe engine. when the key is on, the passenger side fan comes on automatically and stays on? is this the AC fan and what is the cause of it to come on. When i pull out the FAN1 relay it stops. Also what do FAN2 and FAN3 relays control?

While it's hard to say without carrying out a diagnosis, this fault is most likely in the heater control panel on the dash.
Without specific knowledge of the relay configuration of this vehicle, it's possible the other relays relate to cars with multi-zone a/c, which your car may or may not have.
I'd suggest having an auto-electrician check this problem out.