Last night i cut the wires to the temp sesor on the back of the cylinder.
If I twisted them together or left them unhooked it didn't matter. The fan only came on when the engine started.Cool with me. There is 3 wires on it and I tried it everywhich way and it was the same. I started it several times last night, no problem. Today, the fuel pump primes and the motor just spins over & over. I just quickly check all the fuses and there good.
WTF???? someone help me out as I just got this bike.

 

Most bikes ECU's rely on that temp sensor info, and simply unplugging it will mess it up.....

 

I will hook it up after work and run a switch directly to the fan. I am used to the 03's where the switch is on the radiator and its only 2 wires. I was thinking this 3rd wire sends a signal to the ecm or something. Its still weird how it cranked fine several times last night
If i killed the ecu i will be furious,....at myself

 

Well the 03/04 is differnt because it has both the temp sensor in the back of the head to send temp info to the ECU, and a temp sensor on the rad to turn on the fan....So on that bike unpluggin the one on the rad doesnt affect how the bike runs because it still gets head temp info from the temp sensor on the back of the head...Im sure if I unplugged the one on the back of the head on the 03/04, it also wouldnt run properly or even at all...

And I wouldnt worry about frying your ECU, it just wont run without that info in alot of cases....Most ECU's use head temp readings to determine FI and the auto fast idle (choke)....By unpluggin it your ECU has no idea how warm your bike is and what fuel mix to give it, or weather it needs fast idle to warm it up....

 

Thanks, makes sense. I will solder it back together this evening and cross my fingers That Magura bracket should be here Monday. I forgot to tell you that I will need the shorter of your 2 stays