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Fan switch, or ECU controlled?

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Old Mar 24, 2006 | 08:12 AM
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Default Fan switch, or ECU controlled?

Just a quickie, are the rad fans ECU controlled? I cant for the life of me find the fan temp. switch if they are not

I want to wire up a by-pass switch, I assume there is ground or +12v signal from the ECU I can switch to activate the fan relay?

Cheers for any help
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Old Mar 24, 2006 | 08:13 AM
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ECU IIRC
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Old Mar 24, 2006 | 09:34 AM
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ECU
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Old Mar 24, 2006 | 09:36 AM
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Doesnt anyone know which pin controls the Relay?

Cheers!
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Old Mar 24, 2006 | 10:24 AM
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you can just run 12volts to the fan motor..

3 wires from memory.. red (12v) white (variable speed) black (ground).

I THINK I just ran 12volts to the red wire and the fan runs at full speed..

check with a volt meter to be sure though.

Simon
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Old Mar 24, 2006 | 10:29 AM
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Would rather fire up the relay manually, makes much more sense, a lot less load on the switch and wire, especially for that kind of length too.
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Old Mar 24, 2006 | 12:15 PM
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true I did use thick wire..

what year is it?
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Old Mar 24, 2006 | 12:19 PM
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on the phase 1 for example the ecu drops the voltage from 12volt to 0 to switch the relay.. therefore if you find that wire to the relay and ground it..
the ecu will still be sending 12volts down it..

My electronics knowledge is not huge but I think you need to run a new relay or wire straight to the fan like I did.

Simon
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Old Mar 24, 2006 | 12:39 PM
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So if I cut the feed to the relay it should come on?

Will get the multi meter out and give it a crack.. cheers
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Old Mar 24, 2006 | 10:15 PM
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no I think it would need you to cut it and ground it.. but check!
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Old Mar 24, 2006 | 10:26 PM
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Bloody hell, just asked the same question on my thread!
(Davey): Please sort it and post on here asap.

Graham
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Old Mar 25, 2006 | 08:13 AM
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Wont have a chance to play for a while as we're off to a wedding..

Got a horrible feeling the thermostat isnt opening as soon as it should either, I let the car warm up to half temp on the gauge (took a while) then checked the bottom hose, it was stone cold!
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Old Mar 25, 2006 | 04:40 PM
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Can't i simply rig a switch to (on closing) send 12 v to the fan relay (same pin on the switch that the ECU pin is connected to) and that will trigger the relay to close and send 12 v to the fans?
If the manual switch is 'on' and the ECU sees a water temp high enough to signal 'fans-on' then the relay is simply closed when it tells it to, so 'safe'.

Is it realy that simple?

Help!

Graham
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Old Mar 26, 2006 | 07:24 AM
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Help!
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Old Mar 26, 2006 | 07:03 PM
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Just thinking about this. Unless the rad fans are 'sealed' to the rad/FMIC (which mine are not) the fans switch on will have little effect on force cooling the FMIC core?

Is this a waste of time??
Graham
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