I have a 350z 06 and replaced my cooling fans recently due to my previous one breaking down. My car started to overheat when idle, however it runs normal temps when driving around. I checked the fans and seems like only the passengers side cooling fan was activating when I turned the ac on. Are both fans supposed to spin when AC is turned on? My HVAC heat also does not work, but the AC blows cool air when on the cold setting. Any help would be appreciated, if they are both supposed to be on I'd imagine it's a bad fuse/ relay.

 

Yes, both fans should be running when you have the AC turned on. Check your fan relays, they're at the IPDM E/R.
Good Luck!
-Icer