My fan just quit working completely however the AC compressor functions. I don't know how to trouble shoot this situation. Some folks say its a relay and others say its a resister. If its the resister, I have been told the entire blower motor needs to be replaced.

The relay is a common point of failure. Disconnect your baytery. Take off the.plastic trim over Fuse Block -J/B which is in the driver seat footwell (entire cover not just the little access window), unbolt the fuse block so you access the back of it. There will be BLUE colored relays, either 2 or 3, swap them and see if your fan turns back on.

AutoZone carries the OEM Nissan relays if that's the problem.

Nice! I'd hope so.

I went to AutoZone and these relays are about $33.50 each. There are four of them on the back of the fuse box. I don't know if one or all are bad. If I pull the trigger and this doesn't work, I will have $143 total in relays. Nobody has all four in stock so I am special ordering them. Is there any chance the blower motor is fried and I am doing this for noting. What do you all think?

Anything is possible and it is never a good idea to throw parts at a problem unless you are rich lol. Follow cleric's advice and swap the relays one at a time to see if you can find a bad one. If you do then you're only out $34.

Number the relays 1-4 with a sharpie, swap two and see if the fan turns on, if not swap another one, if not swap the last one. If the fan still doesn't turn on and you have tried out all of the relay swaps then something else is going on with the system, the chances of you blowing four relays on four totally different systems is incredibly low.