I left the car idling last night and it overheated and threw me a p0118. The fans won't come on, I checked the relays and fuses and they're all good. And clues guys?

 

Thermostat does not control the fans. If the coolant temp rose too high and the temp sensor KNEW it was running hot, the issues is with the cooling fan circuit, not the thermostat.

If a car overheats while sitting idling, the thermostat could be just fine, but the radiator needs airflow, even for a brief period of time (cooling fan)

I'm still new to the Maxima as my main car, but this applies to all makes....

I'm thinking either temp sensor or fan circuit. (motor, relay, etc)

 

Sorry.

Deleting faulty post.

 

I agree.
Did you check the fans them selves to make sure the motors didn't puke? Spin them by hand (with the car off). And how did you check the relay? Id recommend finding another of the same relay and trying that. Id also make sure the fan is actually plugged in!
Good luck.

 

Both fans are plugged in, and I applied voltage to them and they spun. I sent voltage to the fan relays 1, 2, 3 and they clicked. I also checked the fuses for fan 1 and 2 for continuity. I recently replaced the radiator but I don't see how that could cause this problem.

 

Well we are getting somewhere. Did you try another relay of the same type? Just because it clicked doesn't mean shes not fried.

 

Will the A/C fan come on at all if you turn the A/C on while at normal operating temperature?

 

Hey man, no need to apologize, just giving my 2 cents

 

Two of everything going at the same time is really unusual...tomorrow I'll apply voltage again and watch for it making and breaking at the switched points.

 

Let us know what you find.
I may be interested doubly because I have yet to hear my cooling fan come on, in my '02. (has not seen really any stop and go yet though)

 

Let it idle for 15 or so mins, it will come on. Anyway I found the problem. A loose connection to a fuse box. We were working fast outside in the January weather to swap the entire drivetrain, so one connector didn't get pushed in all the way. I double checked everything this morning all is well. Thanks for effort guys

 

I didn't know you did a swap, but had a hunch about a loose connection! Glad you found it and hope it didn't overheat too bad.