v9x engine fan test

nissan_510 · Dec 30, 2016

gday fellas, just wondering if anyone knows how to test the engine fan?
i thought it was viscous but then how does it switch on with the a/c? reason is i can't seem to get it to turn on, and my a/c goes warm when i stop moving.
can't find any related fuses or relays, any help is appreciated, cheers guys.

jonney · Dec 30, 2016

you can un plug the wire join plug that comes from the fan and with 2 x pieces of wire hold one on the positive and the other to the negative side of plug , other ends go to a 12 volt battery. this will let you know if the fan works or not. i would say it could be the fan relay at fault.

Old.Tony · Dec 30, 2016

The main fan (mounted on a viscous hub) engages purely from heat. There's a bimetal spring in the front that reacts to heat and at about 96C it will turn enough to engage the clutch, releasing it again at around 91C. It does not matter what accessories you use.

The electric thermal fan is engaged when the coolant temperature exceeds 104C or the air conditioning is turned on (YD25 models). The V9X doesn't appear to have an electric fan - at least, the manual is not clear that one exists. It certainly describes an electric cooling fan for the YD25 (where air conditioning is fitted) but there's no mention of one in the V9X section. If you have an aftermarket one, it'll be controlled separately.

nissan_510 · Dec 30, 2016

thanks for the replies fellas, yeah i can't see any electric fans, but i read somewhere that the engine mounted fan also had an electro magnet on it, and looking at mine it does have a connector coming off it. just can't find any fuses or relays to check it as its definitely not switching with the aircon. any ideas?

jonney · Dec 30, 2016

sorry i thought you had a thermo fan like the d-22,s have, plus viscious fan hubs.

nissan_510 · Dec 30, 2016

would anyone have access to a wiring diagram that would include the "electronically controlled cooling fan coupling"

Old.Tony · Dec 30, 2016

I've looked through the manual already. The only mention of 'fan' is in relation to the 40A fuse and the two relays controlled by the ECM. One of the relays is integrated in the IPDM/ER and the harness goes from there to the front of the car. The manual lacks clarity, unfortunately.

landmannnn · Jan 1, 2017

nissan_510 said:
thanks for the replies fellas, yeah i can't see any electric fans, but i read somewhere that the engine mounted fan also had an electro magnet on it, and looking at mine it does have a connector coming off it. just can't find any fuses or relays to check it as its definitely not switching with the aircon. any ideas?

Yes, the manual references an electric fan or a viscous crankshaft driven fan. In fact the V9X has a crankshaft driven fan controlled by an electromagnet.
This fan is engine temperature linked, from the graphs supplied it looks like the coolant fan pays no attention to the air con!

nissan_510 · Jan 1, 2017

i ran the car up to 103deg (which is beyond the temp its meant to act) and could easily stop the fan spinning with my hand, also can not seem to trigger the electro magnet in any way either. what would the chances be that my viscous and magnet components are stuffed? unlikely id say? any idea where to start to diagnose the problem beyond what I've tried already?

jonney · Jan 1, 2017

you might have to replace the fan hub.

landmannnn · Jan 2, 2017

landmannnn said:
Yes, the manual references an electric fan or a viscous crankshaft driven fan. In fact the V9X has a crankshaft driven fan controlled by an electromagnet.
This fan is engine temperature linked, from the graphs supplied it looks like the coolant fan pays no attention to the air con!

Actually I am wrong, looking at page 1247 on the EC manual, the cooling fan control is far more complicated and does look at the air con.

Looking at the description, the electromagnet isn't on/off but is actually used for controlling the fan speed by pulsing. So spinning by hand isn't going to tell you very much.

Old.Tony · Jan 2, 2017

landmannnn said:
Actually I am wrong, looking at page 1247 on the EC manual, the cooling fan control is far more complicated and does look at the air con.

Looking at the description, the electromagnet isn't on/off but is actually used for controlling the fan speed by pulsing. So spinning by hand isn't going to tell you very much.

The wiring diagrams (that I was looking in for a connection) isn't any better at providing an answer. However, there's a way to tell if the fan is engaging. It works regardless of the method of engaging the fan (electric or bimetal).

Drive the car with the stereo off and the windows down, A/C on low, UP a hill that you can drive straight over (you need to NOT turn the car around on the hill, you NEED to keep moving). Drive it hard enough to raise the coolant temperature to over 100C (probably try and get it between 105C and 110C, but NO higher to avoid damage. At this point the coolant fan should be fully engaged.

Crest the hill and take your foot off the throttle. You should be able to hear a loud rushing sound due to the air being hauled through the radiator/intercooler/condensor. As the coolant temp drops (which it will do, rapidly) your engine will go very quiet. If that transition occurs, your fan hub is working normally.

As I said, this one of the tests I use for my viscous hub but it should work for an electrically engaged hub too.

The manual is unclear about when the fan is fully engaged but it should consider 110C to be near the upper limit of tolerance for the engine operation, because of the materials used in the motor. In the YD25 it specifically states 105C as the point when the electric fan will come on to assist (if the air conditioning is turned off).

nissan_510 · Jan 2, 2017

Tony, I've heard it roaring before, even yesterday when i started the car it was already engaged and roared for about 10 seconds then switched off, the problem is i revved the engine up to 103deg in park with aircon on and got nothing. just had the old mans 550 over here, could not get the fan to engage via the aircon, tried it in low range reverse also to see if that may have triggered it and got nothing, but it did flick on just by coolant temp at about 89deg. which mine won't .
so landman are you saying its viscous that drives it and fan speed is electronically controlled?
so if mines not coming on with temp then my viscous hub must be stuffed? nothing electrical to do with it? or can the magnet engage the fan regardless of the viscous component?
thanks for your help again guys.

jonney · Jan 2, 2017

you can buy an after market viscious fan hub off ebay . don,t buy a genuine one unless your pocket is full of dollars.

Old.Tony · Jan 2, 2017

It might not be a completely viscous hub. It seems the hub's electromagnet does the engaging by pulsing power to it - the more frequent the pulses, the firmer the engagement. You'd have to make sure any aftermarket hub was made the same, and you'd want to be sure that your electronics aren't actually the thing at fault.

What's the chance of borrowing your father's fan unit?

nissan_510 · Jan 2, 2017

yeah exactly what I'm trying to find out, no point buying a new hub if its not at fault.
but if i don't know how to trigger the damn thing, really need a scan gauge that can trigger it that way, prob gonna mean a trip to nissan which i was hoping to avoid

there should be a way i can do it myself, i believe the electronic control is sent via CAN which I'm not all that familiar with.

landmannnn · Jan 4, 2017

A couple of things to think about....

The BCM will control the electromagnet by PWM (pulse width modulation), you will be able to monitor this with an oscilloscope, however you should be able use a multimeter on the alternating current setting to see if a voltage is being applied.

As far as the triggers, they are
Engine speed,
Coolant temp,
Refrigerant pressure,
Road speed,
Coolant fan speed,
AC on
AC blower on,
Intake temperature
So running it up to temperature in neutral probably won't trigger it.

This level of complexity means that without knowledge of the source code and a lab, the only diagnosis tool is to swap the bits until it works. That's what Nissan would do.

Old.Tony · Jan 4, 2017

landmannnn said:
This level of complexity means that without knowledge of the source code and a lab, the only diagnosis tool is to swap the bits until it works. That's what Nissan would do.

And that's NOT because the average Nissan tech thinks that a lab is something that helps a blind person.

It would be interesting to see the guts of one. What makes it fail? Does it work like the electric brakes in a trailer?

johanvdm · 2025-03-05T02:41:00+1100

Hi guys. I have also got the dame issue. V9x fan keeps running,have replaced the clutch but same damn issue!! Any advice??

v9x engine fan test

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