Thread: Cooling fan not activating.

That is a last resort. First I need to confirm my one fan works. Then confirm if fan switch works. Pics of the location would help. And if there is a way to test it.


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check the engine temp sensor, mine was broken once and wont let my fans come on

Hey Mark, I'm having the same issue. One question to ask is are you using an aftermarket large aluminum radiator? I spoke to GregV directly the other day and he said that sometimes if you have a large enough radiator the fans might never turn on do to the fact that you've got efficient enough passive cooling. That being said, I am currently experiencing the exact same issue as you. I had went to Nissan of Puyallup myself and purchased the water temperature sensor for a lowport engine and swapped it in one evening after learning that my fan wasn't activating also. That next day I ran the vehicle around the block and got it up to temp and popped the hood and found out that my fans had turned on. That was about a month, maybe two months ago.

I have now completed my VE swap and I've yet to see or hear my fan turn on since then. The ambient temperature (it's been a lovely past few days in Washington, hasn't it?) plus my fat ass of a radiator (mizu, from JGY) could potentially be enough to keep my coolant low enough, assuming that I'm constantly moving and not stuck in traffic. I'll be running through the relays and fuses/fusible links myself and see if that all checks out. I'd hate to have to replace my sensor again but if that's what it takes to get those damn fans running I might bite that bullet.

As for reference, if you are standing in the front of your car looking into your engine bay the sensor we are talking about is to your left on the back of the block right under where the intake manifold ends. If you stand in front of your passenger side wheel you can see the sensor. It's a bitch to get to and I have no idea how your engine bay is set up but I found it easier to access that sensor by removing my ABS unit. Damn thing is in there tight.

Edit: the OEM nissan part is like 40? bucks. My part guy was a dipshit and didn't know what I was talking about so I had to hold his hand the whole way. At least I looked good in front of the cute desk girls. Also if you haven't already, bug @GregV for your parts. He's down in california and shipping through him only takes a day or so to reach me and I'm only an hour south of you. It would be no faster than ordering through the dealership and you won't have to sell your balls to get a stupid sensor.

Is the drivers side fan still installed? This is the main fan, the one on the passenger side is the AC fan. If you turn on the AC does the fan come on?

What about pulling the interior A/C fuse and turning the A/C on, see if fans come on then

Yes I have an aluminum radiator. Any idea of the part number for the sensor? Again. I have a vvl motor but not sure I have low or hight port


I'll have a look to see if I can find the switch

The only fan I have is in the driver side. I'd be interested in trying to find the interior ac fuse. The one under the hood is already gone.


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All VEs are considered low port. I can't recall the part number but as long as you get the plug from a low port you should be fine.

If you have a datalogger, like a consult cable, you can check to see if your temp sensor is working like it should.

Here's the stock fan output parameters, from Nismotronic documentation


Wiring a constant ON/OFF switch seems like a recepie for disaster IMO, all it takes is one time to overheat!

For the normal person yes, but I am highly and seriously, obsessive compulsive. I glance at the fuel gauge and temperature gauges like every minute, at least for a brief moment when idling/driving. IDK why. Never stopped and I don't know when it started. Plus running distilled water and Redline water wetter as coolant, having no A/C and the heat w/ windows down (when warm out) on at least on setting 1 helps.