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Can any of you guys guide me through attaching a toggle switch to over ride the ECU. I want to be able to hit the switch when things get hot, and get the fan going before it’s too hot?
There is a blue and a black wire coming out of the fan, can I attach to the blue wire up to my toggle switch and down to the positive to make a circuit, or is it more complicated than that?

Cheers, Craig
 

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I'd be running it through a relay with a fuse in line as well. And you'll want a waterproof toggle too.
As far as the ECU goes I'll wait for the experts to say whether it can remain connected normally as well or whether it then has to be completely on the toggle without anything going back to the box. I can imagine a diode may be required to prevent back spill of current. No doubt someone will tell us soon.
 

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Mine uses a mini toggle switch with a rubber boot on the clutch bracket. It is fed power from an auxiliary fuse box under the seat which uses a relay to switch on with the ignition. The switch provides power to the fan by tapping in to the positive wire.
The ECU still controls the fan when the switch is off but you can choose to turn it on at a lower temp.
You could also get power from the main ignition relay through a fuse to the switch or maybe even better, from the hot side ( terminal 30) of the original fan relay. None of these set ups will effect the ECU operation.
 

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I would use the Fan relay. You could splice into the Test socket power supply which is ignition switched and under the seat and run that to your switch then back to the coli of the Fan relay sitting under your seat too (as per St4S 2002) and close to the test socket
 

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This is the thread that contains the most complete set of directions, ones that I used successfully on my 2003 ST4s, which is what I believe you're asking about.

http://www.ducati.ms/forums/40-sport-touring/40740-fan-relay-bypass-question-3.html

The only adjustment I would make on grimah1w's discussion is to secure a more robust switch. I have used smallish ones successfully, but now believe that a larger switch would be able to handle some of the hotter times a little more elegantly.

There are several other threads around that discuss the issue.

Ron
 
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There is a far more elegant solution that makes use of the relay and does not need a switch to handle full fan current.

I posted that in the fan relay bypass thread here http://www.ducati.ms/forums/40-sport-touring/40740-fan-relay-bypass-question.html#post6741601

It applies to any model, brand whatever where the ECU switches the fan relay coil to battery negative.

That is the whole point of a relay, where a low current connection/signal is used to switch a high current switch (aka relay)

It also gets rid of the need to know wire colours, so is brand/model/year independent.
 
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Can any of you guys guide me through attaching a toggle switch to over ride the ECU. I want to be able to hit the switch when things get hot, and get the fan going before it’s too hot?
There is a blue and a black wire coming out of the fan, can I attach to the blue wire up to my toggle switch and down to the positive to make a circuit, or is it more complicated than that?

Cheers, Craig
Man you are impatient! You only sent an SMS last night that you did not understand the stuff sent by email.

Lucky you are a mate otherwise I would take the piss out of you!

Mmmm well I do face to face:laugh:

OK - can't help myself, hopefully the instructions are Craig ready>:)
 
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