# Help finding the fan switch!



## fugiot (Jun 27, 2003)

Ok, in my 94 SE-R, my fans won't kick on when the car gets hot. I've tested both of the fans from the connections directly behind the radiator and they both turn on. 

So where's the little thermoswitch dealie that tells the fans to turn on? And if it's not that switch, what else could it be? My temp. gauge works, so I don't know what else to look for.


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## 95 SentraB13 (Jun 14, 2002)

Possible problems:

- Cooling fan relay is burnt out or corroded(located in holder next to battery)
- Thermostat may be stuck/malfunctioning
- Thermistor(temp sensor) needs to be replaced
- Wiring/ground problem


I have the same issue with my GA. The fan comes on when I either hot wire it to he battery or unplug the thermostat temp. sensor plug. The fan is always off when the car is running with the sensor plugged in or if I do a continuity test on the harness.

The FSM says, for the SR, that the engine coolant temperature sensor(ECTS) is located behind the oil filter. For the GA it's a red connector located on the intake manifold behind the valve timing control(VTC) solenoid valve.

Another thing I notice is that I'm burning excessive fuel, beyond what I would consider normal. Granted, my speed sensor(VSS) isn't working either so that could also attribute it to running in limp mode and causing it to run rich. My temp. gauge also works fine yet it never rises above the 1/2 way point no matter what the outside temperature is.

If you figure out what your problem is or get someone else to fix it for you I'd love to know. It seems a few others have been having a similar problem based on what I've read lately.


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## fugiot (Jun 27, 2003)

Yeah, I found that ECTS thing and I tried to make a jumper to connect the two wires, but the fans didn't come on. Does jumping that connection turn the fans on? Or should I just replace the whole sensor and find out if that was it? And it wasn't my thermostat cause I replaced that right before I started this thread. Any idea how much a new ECTS would be? $5-10? $15-30? More?


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## 95 SentraB13 (Jun 14, 2002)

fugiot said:


> Does jumping that connection turn the fans on? Or should I just replace the whole sensor and find out if that was it? Any idea how much a new ECTS would be? $5-10? $15-30? More?


With mine, when I unplug the ECTS harness the fan turns on; if I plug it back in or run a continuity test(jumping) on the harness connector the fan goes off again. You can hot-wire the fans to the battery and install a switch but to me that's avoiding an obvious problem and creating an unnecessary wiring mess. Based on the FSM, the continuity values I'm getting seem correct so it may not be the sensor, although electrical troubleshooting is not an area I excel in.

You can try the trial and error approach if you like but I have no idea how much a new ECTS would cost. My guess is at least $50. In situations like this I'd just assume take the car to a qualified mechanic or friend to see if they can fix it, despite being the type to perform most of my own repairs.


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## fugiot (Jun 27, 2003)

Damn, so you're saying that my fans should kick on when I unplug that little red plug from the ECTS. Well, that doesn't happen. Is there anything that could be causing a connection failure between the ECTS and the fan plug that's directly behind the radiator? Because the fans work when I test them from that plug.


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## 95 SentraB13 (Jun 14, 2002)

Have you checked the coolant fan relays for corrosion or tested for continuity to see if they are functioning correctly?


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## fugiot (Jun 27, 2003)

where are the relays? In the little black boxes in the engine bay? How should I go about testing them?


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## SPEEDO (Jun 9, 2003)

on a 94 they had problems with the motors, and there is no thermo-switch, start with the connector going to the head temp switch, its in the housing on the firewall side, front of engine, if I remember right it has a yellow two pin connector. try to clean the connectors and see if that helps. or it could be the motors. you might have to do some investigation work. hopefully its just the head temp switch... good luck


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## fugiot (Jun 27, 2003)

you mean the fan motors have problems? Cause those still work. I'll try and find the head temp switch and clean that out. Thanks for the info.


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