Question about the radiator fans on my 01 Nissan maxima gle
 

I was wondering which one does what? I recently replaced my drivers side radiator motor fan cause it would barely come on and when it did it spun very slowly, the passenger fan operated no problem. but I replaced it with a junker one and it works like new now. The weird thing is the passenger one worked Perfectly and since I replaced the drivers side fan it only comes on when I turn the ac on. What could it be and should it have operated like that the entire time? Or am I just being paranoid? The car hasn't overheated btw and has driven like normal.

Both fans are supposed to run at the same speed at the same time. The system is designed as 2 fans that operate as 1. Not sure what could be causing your issue though.

I thought one worked for the ac and one for the radiator.

As others have said, the 2 fans work as one. ALWAYS. Question about the passenger side radiator fan - when you NOT using the a/c, does it work at all?

If you start the car in the morning and the engine is cold and turn on the a/c, does the passenger side fan come on immediately or does it come on after a while as the engine warms up?

I'm thinking that the low speed in the passenger side fan has stopped working and you need to replace it.

The passenger side fan turns on immediately after I turn on my ac

why not just replace the entire fan assembly? a new TYC is $65.

This is what I did. Works great.

Both fans should run when the ac is on. Sounds like you may need a new fan assembly.

both of them do run when the ac is on