ST4 Cooling Fan

hi guys ,
got back from a long ride today, and when i got back and left the bike ticking over it over heated , went upto about 90dgrs, and spat the water out the water cooler, i then noticed that the fan wasnt kicking in !!

i have found the fan relay and when sticking 12v on to the violet white the fan works fine ,
i have shorted the switch out on the sensor towards the front wich makes the display on the clocks show 120dgrs ,
and the other sensor when shorting does nothing ?
would have thort a sort at the awitch would tell relay to work etc or does the ECU mesure resistance maybe ?

i have checked cables from relay to ECU, feed to relay, cable from thermoswitch to ECU, checked resistance at thermoswitch with engine running ok,
relay works ok, looks like ECU problem? think im gunna have to fit a manual switch !!

any ideas guys , :frowning:

BUT … What Temp should it get to before fan kicks in ? does anyone know ?

no one knows !!!

hi,i think they can run up to 105-106 deg c before they kick in,if their reading out due to calibration this could change.
I have a 1098 and checked the settings with tuner pro and it was set at 103.I dropped it to 98 to help cooling

thanks dave ,

My Multi come on at 104c if that’s any help?

all sorted , neck of radiator had cracked , causing over heat at around 85dgrs, had it welded up, even polished all the ally while it was off mmm and all good gets upto 105 then fan kicks in , wd40 is also a god send on crappy conections