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I don't know what a March is, not sold in the US under that name. But I would suspect on that newer a model, the ecu turns the fan on when the Coolant Temperature Sensor on the engine registers a hot coolant temperature which requires the fan for extra cooling.
On older model Nissans (like my '87 Sentra) there is a switch about half way down on the radiator (look for a 2 wire connector to it). When the coolant temperature reaches 192 degrees F., the thermistor contacts close, and the fan relay turns the fan on. When the temperature drops below 181 degrees F., the contacts open and the fan stops running.
You could verify fan motor is good by using jumper wires from battery to the fan motor. If the motor is good, you will probably need a wiring diagram and at least a test light to start checking the fan circuit. There will be a cooling fan relay that when signaled, will send power direct to the fan. The signaler to relay to turn the fan on may be the engine computer when the coolant temperature sensor tells it engine is getting too hot- or it may be signaled on by a fan temperature switch mounted in the radiator. When coolant reaches a set temperature the switch closes contact, and the relay is energized to pass power on to the fan. One could pull the relay and with key on, use test light to probe the terminals where relay plugs in. The power feed for the fan should light up the test light on one of the terminals, verifying power is still available to turn the fan on. Next one could check if the signaler to turn the relay on is working. See? So you do need a wiring diagram to see how the circuit is wired. But the first step is to verify fan motor is good. Good luck, Nigel.
if engine over heating coolant over flow jug will boil over you will see steam.sound like you have either faulty engine coolant temperature sensor or could have faulty fans relay or fuse or pcm problem if coolant fans dont turn on.have garage with code scanner that can do a snap shot on coolant temperature sensor check see how hot coolant temperature is see if coolant temperature over 220 degrees engine getting too hot.could have faulty water or blowed head gasket check engine oil on oil dip stick look milkly you have blowed head gasket. i use infra red laser thermometor check see how hot engine is over 107 celsius engine is overheating.
You need to change the relay and the temp sensor switch. If you have done that the reason it's not coming on is probably because the coolant is not
getting hot enough to cause it to come on. Let me explain. The coolant
fan when the A/C is off is activated by the coolant fan switch. The
switch closes when coolant temperature is over 238F completing a path
to ground through the coolant fan relay windings. The relay contacts
then close and voltage is applied to the coolant fan. When the coolant
temperature drops to 214F, the switch opens and the coolant fan stops.
In A/C equipped vehicles, the A/C control head completes a path to
ground for the coolant fan relay whenever the A/C is on no matter what
the temperature. Voltage is then applied to the coolant fan.
Essentially, the coolant fan switch is by-passed when the A/C is on,
which is why the fan works whenever you turn the A/C on. Now, if the fan
does not kick in when the coolant temperature is over 238F but works
when the A/C is on, the problem has to be the coolant fan switch or the
connectors or wiring to the CFS.
CHECK COOLING FAN FUSE AND RELAY.IF ALL IS GOOD.HOT WIRE COOLING FAN TO MAKE SURE COOLING FAN MOTOR IS WORKING. IF COOLING FAN RUNS WHEN YOU HOT WIRE FAN MOTOR.CODE SCAN FOR ECM FAULT CODES.REPLACE THE ENGINE COOLANT TEMPERATURE SENSOR NO NEED TO BYPASS THE SENSOR.
iam suspecting the temperature gauge here ,something is or could be wrong with its electrical conductivity ,or the cooling fan is coming on too late which could be caused by a similar problem with the fan temperature switch
Most often that is caused by a bad thermostat.
How to test the thermostat in most vehicles;
Make sure the heater is off, start the engine and let it run for 6 to 8 minutes, ( this will allow the engine to reach, " normal operating temperature "), from the inside of the vehicle turn the heater temperature on high and turn the fan speed on high. 1. Listen very closely for a click sound from the engine, ( most thermostats make a click when they open ) 2. Watch your temperature guage, it should begin to lower as the coolant starts to circulate. 3. Usually within a few minutes the radiator fan will kick.
What the thermostat does;
It seperates your coolant into two parts. The first part is in your engine, the second part is in your radiator and the coolant reservior. When the coolant in the engine reaches the temperature rating on the thermostat the thermostat opens to allow the two parts of coolant to change places. Now the cooled coolant in the radiator and reservior flows into the engine while the heated coolant flows from the engine into the radiator and reservior to be air cooled by the radiator fan.