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Discussion Starter #1
Hi ,read through as much as possible on fan not cycling on and off and can not figure out my problem . New thermostat ,no change ,new temp sensor on cylinderhead ,no change , old rad had a bend on bottom so replaced rad and hoses with a good clean rad.new antifreeze .fan cuts in and will not shut off unless i turn the key off and then it shots off .If i disconnect the temp sensor the fan cuts in as it should if i put a little cold water on the old or new sensor the fan will shut off . the machine does not seem to be running hot and i can feel the temp change in the rad and the hoses as the thermostat opens and closes . when i throttle i can see the rad hose neck drop and seems like good circulation . It seems to me that the thermostat is set at a higher temp than the fan so the fan will always run . never checked the resistance the switch but new and old switch are working the same .hot light is not flashing . I can feel the right side of the rad getting hot then cooling off .Any suggestions would be appreciated ,thanks.
 

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Sounds like you covered all the points. Which makes it even harder to make any suggestions. Two things are coming to mind one try burping the machine to make sure there aren't any air pockets. Two even though the radiator looks clean they aren't. Especially on your machine with the rad down low. I would remove the radiator and thoroughly clean it then inspect it to make sure you can see through the fins. Then burp the machine to remove all air pockets.
 

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Discussion Starter #5
Hi,i raised the machine about a foot on the front and ran it and topped it up until it would not take any more.The rad is clean inside and out and the hoses also as i replaced them .I can recall reading somewhere that the early 700 had a resistor that you could install to change the resistance on the switch but cant find where i read it. Only things not changed are the water pump impeller and ecm.I do think that the temp switch is creating too much resistance but not enough to cause the hot light to flash.Thanks for your suggestion and I hope others will chime in with their thoughts , there is a wealth of knowledge on here and hoping some of it will work for me ,thanks again.
 

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Wait you said in your second post the ecm has been changed???????
 

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Cause if it hasn't then that's your problem. Assuming all you T's are crossed and I's are dotted.
 

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Discussion Starter #8
Hi not sure when the ecm was changed but it has aluminum fins and i had the dealer run my vin and they said everything was up to date on the machine .I have read that the ones with ecm problems ,the fan stays on after the key is turned off . My fan shuts off when i turn the key off .
 
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