Only 1 fan working????

[SouthflA4]

I noticed today my a/c started blowing warm. I checked it out and noticed neither fan were spinning, I started to freak out. We tried to see what we could find and nothing. So i let the car run at idle for a little bit and noticed the car wanted to start to overheat. I shut the car down and let it sit and waited about an hour. Drove the car home with no a/c on which was only 5 mins away and when I got there i turned the a/c on. What do you know, the right passenger side fan came on finally and it started blowing cold again, but i let the car run again for about 10 mins to see if the other fan would come on and it didnt.

I tried searching and couldnt really figure out why just the a/c fan is working and not the other fan. Please any ideas let me hear them?????

[A4ringedONE8T]

Most likely the lower coolant sensor

[SouthflA4]

Is that the G83 sensor???? And is the function of that sensor to tell the fan to kick on isnt it???

[SouthflA4]

Somebody please tell me.....i dont want the stealership to rape me for a diagnosis hook up. What do i need to replace to get the driver-side radiator fan to kick on????