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Discussion Starter #1 (Edited)
The thermo fans on my 999 are not running. Both fans are supplied with 12v positive from the battery (unfused according to the wiring diagram), and the switching of the negative is done by the ecu. (This can get confusing for some. Electron flow in Australia is from +ve to -ve, whereas in in the US they flow from -ve to +ve). There are no relays.

Thermo fan function then is controlled by the ecu, so if the engine temp sensor is functioning ok (as exhibited by the dash and IAWdiag), how do I fix it?

EDIT
I've just read some past posts that state the fans don't come on till 220F, or 104.4C. Is this true?
I only got up to 104C today, so technically they perhaps should not have come on?? It was ambient only about 28C here, and we get days to 38C.

Can it be reprogrammed?

Regards, Greg.
 

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All ECUs, when switching 12V nominal devices, switch/ground to negative.
ECUs run on 5V nominal so the only way to handle 12V devices is to switch/ground to negative.
Is IAW Diag showing sensible TP, RPM, Temps etc.
ScanST shows many real time parameters.
BTW, Greg and I spoke for the first time this morning for an hour or so to swap knowledge and more.
I have not looked at the 999 wiring diagram, but with the ECU unplugged from the harness and grounding the fan control pin in the harness, do the fans run? Obviously they need to have 12V even when the ECU is unplugged and hence maybe not closing a relay that powers things up.
 

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Discussion Starter #3
No, no,no, and NO! I am NOT stripping the bike again to access the ecu again. ?. I'm totally over that! It'd be easier to fit an auto/manual switch c/w thermocouple until I find the software switch IN the ecu programming.
 

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If the fans dont get power you will get a Check Engine Light. These bikes have to get very very hot before the fan turns on, they are retrofitted air cooled motors don't forget. If you dont have a check engine light, its likely you didnt let the bike get hot enough (your not the first). Try again and let it get to 220 or so, if you want to make yourself feel better about it before you try that, unplug one fan, this will cause the other to run constantly, you can check both this way.
 

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Discussion Starter #5
Yep. You are 100% correct. The fans do not run at ignition on, but when I unplug the left fan the right fan runs permanently. 220F seems very high to me, but if that is what it is, it must be for a reason. If I get the bike over 220, will the fan keep running when I turn it off to cool the fluid and cause circulation?

So if I interrupt the cable from the fan to the ecu with a single pole change over switch (connecting the ecu cable from the fan to ground, and leave the ecu cable float), on say the left fan, will this give me manual control of the right fan with a warning light (check engine light) to remind me it's on manual? Or will it give me other unwanted side effects like my medication does?

Regards, Greg
 

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220F or 104C is pretty much the norm from what I have read.
Unplugging one fan and making the other run full time to me means the ECU is doing what it should.
It goes into "there might be a problem" mode and better to be safe and sure and run the remaining or sole fan
That happens when people load two fan bins into a bike equiped with one fan.
In this case I would just trust that the ECU is doing what it should.
In another thread of yours about the 999 you have, I posted an XDF by Meinolf.
Fairly sure in that XDF and Tunepro you can change the kick in and kick out temps for the fan.

My bike is air cooled so none of this extra stuff to go wrong.
 

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Discussion Starter #7
I'll look at it in Tunerpro. I've been working on the 3CL this arvo. Sometimes I just love simplicity..

PS that would be the beta4 xdf?
 

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Yep. You are 100% correct. The fans do not run at ignition on, but when I unplug the left fan the right fan runs permanently. 220F seems very high to me, but if that is what it is, it must be for a reason. If I get the bike over 220, will the fan keep running when I turn it off to cool the fluid and cause circulation?

So if I interrupt the cable from the fan to the ecu with a single pole change over switch (connecting the ecu cable from the fan to ground, and leave the ecu cable float), on say the left fan, will this give me manual control of the right fan with a warning light (check engine light) to remind me it's on manual? Or will it give me other unwanted side effects like my medication does?

Regards, Greg
104 degrees is the fan switch temp on almost all Ducati's, if you stop the bike the fan will keep going until the temp falls to the point that it turns the fan off but the only way to have circulation is via the mechanically driven water pump, so no, without the engine running there is no circulation.

Have you ridden it and had the water temp get that hot? if not you should do that before modifying anything, the std fan set up works well, usually it requires some stop start traffic and a hot day to provoke the fans into working, if they don't i'd suspect the sensor in the radiator before the ECU
 

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Discussion Starter #10
It got to 104C in traffic yesterday, and it was only 28C ambient. I've only found 1 sensor on the motor that feeds temp to the ecu, and the dash and iawdiag show it is working. I think it is a case of they were about to cut in when I got going and the temp dropped. I'll see how it goes. Winter will help...Regards, Greg
 

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220F or 104C is pretty much the norm from what I have read.
Unplugging one fan and making the other run full time to me means the ECU is doing what it should.
It goes into "there might be a problem" mode and better to be safe and sure and run the remaining or sole fan
That happens when people load two fan bins into a bike equiped with one fan.
In this case I would just trust that the ECU is doing what it should.
In another thread of yours about the 999 you have, I posted an XDF by Meinolf.
Fairly sure in that XDF and Tunepro you can change the kick in and kick out temps for the fan.

My bike is air cooled so none of this extra stuff to go wrong.
I'll look at it in Tunerpro. I've been working on the 3CL this arvo. Sometimes I just love simplicity..

PS that would be the beta4 xdf?
there is a later one inMeinolf’s 59M thread

Edit - here
 
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