Easy Question about cooling fan? How does the Radiator Cooling fan know when to Come

[jeffseby]

How does the Radiator Cooling fan know when to Come On? It may be from the Coolant Temp Sensor, but I thought that wire only goes to the Gauge....?

[rubix777]

doesn't the thermostat trigger the fan?

[crxlvr]

its the thermostat activates it.

[jcrx]

Fanswitch.

[jeffseby]

I concure, the thermostat is a just little spring thing that opens at 180 Degrees, it just lets the coolant flow, it has no electrical connections at all.
Maybe the ECU just activates it every five minutes or so??? but I don't know.

[rubix777]

then why is the thermostat the first thing someone changes, when their fans do not automatically turn on?

[jcrx]

I don't know who that someone is, but if my fan doesn't come on, I change the fanswitch.

[Tofuboy]

There are two sensors/resistors for the ECT. One I think runs on 12V which goes to the gauge on your cluster, the other runs on a 5V reference voltage for the ECU.

The ECU sends a 5V out to the sensor/resistor and reads the voltage after it goes through the sensor to determine the temperture, if necessary, the ECU will send a signal to the fan relay/switch to active the fan.

It's not necessary the fan relay or switch that cause the fan not working, you will have to run a test to check what componet is the cause.

Now for those who read this post and gain some knowledge please send a "civic build up fund" to my paypal account ([email protected]) if you can.

Thank you.

[bryan.az]

i got a 96 integra that the fans dont switch on at all does anytone got any clues, the relays and fuses are fine but still no power to either fan???

[civickiller]

how do you know hte relay is fine ?

[GWInquisitor14]

Tofuboy hit the nail right on the head. When the CTS sends back a certain voltage, it changes that into a temperature and when it gets so hot, it turns the fan on. All the thermostat does is open up to let coolant into the engine. If it didn't, the fan wouldnt turn on because the air rushing past the radiator would always be cooling the coolant and there would be no hot energy from the engine to transfer into it thus no need to turn on the fan.

[almxdupintegra]

It should turn on as soon as you turn on the AC, at least in my car thats how it goes on

[gunnmen01]

theres a 2 pin connecter on the thermostat housing, thats the sensor that turns on the cooling fan... if you want to test that sensor cuz your fans dont run, try using a jumper wire between those 2 wires on the connecter, that should make them run... if the fan works the sensor is bad


gunnmen01