Sorry if this is a stupid question lol but is the door lock actuators for the coupes and the sedan the same? I work at an auto parts store and the only parts coming up are for sedans :/

 

No i dont think they are the same
the sedan is cheaper then coupe

 

If I can still hear it trying to unlock and lock, but it doesn't unlock or lock, does it mean it's the actuator that's out? Or something else?

 

Most likely it is. Do you see the lever move a little? It is a common problem with the G35 .I
bough aftermarket actuators form eBay. Just do a search for G35 door lock actuators and you can find some.Here is the link for the 1 i bough and wow it went down in price. I payed $50 for it and now its $35 with free shipping. http://www.ebay.com/itm/INFINITI-G-3..._qi=RTM1562570

 

They are different . Coupes doors are longer so the cables have to be longer.