I JUST had similar issue with my 97 Vulcan. It had a stuck open thermostat... It would not warm up when cold. That tuned out to be a Defective Fail safe thermostat.. Electrically, the PCM controls the fans. If the two wire PCM coolant sensor is open or unplugged, the cooling fan will run all the time. New Live OBD2 scan for coolant temp readings should verify that issue if it shows out of range coolant temp readings.. Problems with the 4 wire AC overpressure switch will cause issues. (unplug it for awhile and see what happens) If you unplug it and the fans go off, the PCM could be thinking its AC overpressure and running the fans. Bad or intermittent CCRM (or relays 98+) could cause issues since they directly control the fans.. Bad switch on HVAC pod could cause strange issues.. If the PCM thinks the AC is on from the HVAC pod, the fans will run i believe.. I was up all night. Hope this edit clarifys the points
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