# OEM electric aux radiator fan not coming on (05 Path)



## generatorlabs (Aug 8, 2011)

(2005 Nissan Path)

I noticed that my ambient temp reading (the readout on my rear view mirror) was extremely high. Today it registered at about 110 degrees F. That had me scratching my head because I know it was about 90 today. I figured the ambient temp sensor was picking up heat from the radiator. I have also been noticing that the AC will not cool when the truck is standing still. When the truck is moving the AC will cool well. I started to think there was some relation ship between these two events. 

I began to assume that there was no air moving across the condenser and thereby lowering the efficiency of the AC and perhaps not pushing air across the ambient temp sensor either when sitting idle. First I checked the clutch driven fan and that seems normal but then I noticed the electric aux fan was not spinning even when I put the AC on max cool. On my other vehicles (different makes) the electric fans come on with the AC.

So my question is 
a) is this fan controlled by the A/C unit?
b) should that fan be on with the A/C?
c) or is that fan temperature controlled by engine temp or tranny temp?

Any other observations or hints are appreciated.

Thanks


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## Volvite (Nov 12, 2010)

Hopefully I'm not too late to answer your questions.

A) The aux fan is controlled by both the a/c and high temp. 
B) The aux fan should turn on whenever the a/c button is on. Also your vehicle will turn on the aux fan if the engine is running very hot, and will reduce your cooling for a/c as it tries to cool the motor (possible bad coolant/water pump etc causing high temps)
C) Answered in part B.

Hopefully that helps. If that fan does not turn on with the a/c on, then I would try a couple different things. 
1) Check the fuse
2) Disconnect the fan and run power leads from the battery to the fan to see if the fan motor works. 
3) Possible bad fan relay. Swap aux fan relay with same relay but from a known good relay, ie horn or headlights are usually the same relay and see if that fixes the situation.

Let us know what you find out.


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## smj999smj (Jan 1, 2006)

The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, refrigerant pressure, and air conditioner ON signal. The control system has 3-step control [HIGH/LOW/OFF].


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