I'm trying to locate the fuse fan for inspection and to replace in it, but I don't know where it is.
I am the KING of taking the bike apart to find that fuse.
On the gen1, it's inside a white capsule attached to the coolant overflow reservoir frame, right-hand side. Take the panel off the right side of the tank, and you should see it.
Other than faulty fuse, what else could cause the cooling fan not to operate? Any suggestions? Thanks.
I'll bet it's the fuse. Did you crash recently and bend up the radiator? I hear the fan can get physically jammed and then kill itself. (Let's just hope it's not that because those mofos are surprisingly expensive.) Give it turn with your finger (with the bike off) and make sure it spins freely. There'll be a little bit of natural resistance from the fan motor.
Since it doesn't run when grounded, it's probably not the temp sensor.
But assuming it's the fuse, the question becomes: why did the fuse blow? On mine, it's because the wiring harness rubbed through a bolt that was on the coolant overflow reservoir frame. I put a new fuse in, it was fine for about a mile, and then bzzzpt. Shorted out again, and the fuse blew again. I was on the trail, so I fixed it with duct tape (never leave home without it), and that lasted the rest of the trip until I got home for a proper repair.
Might be worth taking the tank off for a visual inspection of the wiring harness.
Or maybe the fuse just blew because it was old. I don't know how often that happens, but it seems unlikely.