A few weeks back my daughters 02 died on her. When I got there it would start and run with foot on gas but bogged down really bad. Wouldn't go over 2000 rpm. Temp gauge was hot. Towed it home and car sat couple days before I had a chance to work on it. Cranked it up and it seamed fine. Only had knock senor code. Drove it a little with no problem. Got home and let it idle in drive a bit and noticed it was getting a little warm. Noticed only one fan was running, the one on the right looking down into engine bay. Even with ac on the right fan only works. As I was trying to figure out the fan issue the engine started to make knocking noise and it set misfire codes on 1 and 6 cylinders. Now I will be replacing engine but need to solve fan issue. Fan spins freely by hand.

 

Fan motor should be a simple check.
Turn by hand, see if it turns freely.
Find if it's getting 12V, and that ground is good.
Pull the plug and check conductivity of the motor.
One of the above must be missing.

 

Just replace the fan motor. They're about $40 or so.
It's the same part for the left or right.
These fan motors do fail.
I've swapped them in both my Maximas and there are several threads on the subject going on right now.

 

Still worth making sure that it is the motor which is the root cause of the problem.

 

I agree in theory. I've just seen many of these fail and it's always the motor. The rest of the system (relays etc...) is very solid.

A quick test it to unplug the motor and hotwire it with power and ground. If it runs it's good. If not it's bad.

 

The fan motor is most likely bad. Ive replaced my pass side fan motor twice/used ones. For the record Both fans should be running at low speed togather. And with the AC on they should both be running.