Fan not working question

[MG#43]

So, have tried 3 fans, none known to be working for sure. Fuse ok and replaced regardless, but my question is, should I see voltage from the fuse box fan connection knowing the fan doesn't actually kick in till the temp hits over 100 degrees? At present no sign of voltage from fuse box.
I have bought a manual over ride switch which obviously doesn't work yet but I hoped would avoid the need to repeatedly reach those temps.
Should this trigger a live connection from fuse box to fan itself, presume so?
Bike is a gsxr 04 if it helps. Anyone got any suggestions? Thanks. Mark

[J.M.]

You'll only measure voltage through the fuse when the fan is both working and active.

The fuse sits on the positive power before the fan. The switch sits on the negative wire after the fan and before earth.

So: Fuse -> Fan -> Switch -> Earth.

With the bike powered on, if you connect the fan to earth directly, bypassing the switch, your fan should spin up (if working). If this works, but when riding it doesn't work, your switch is to blame instead of the fan.

I've derived this from looking at the wiring diagram, not by experience with your bike, so I don't know anything specific.
____________________
2004 R1 & 2018 XSR900

[wristjob]

if you put a 12v supply to the fan does it spin?(i mean power and earth with it disconnected from the bikes usual electrics)
if it spins its not the fan at fault.