Looks like the first test to perform is to disconnect the switch from the harness and place an ohmeter across the 2 lead pins on the switch. You should see an open circuit with the clutch engaged (lever out) and then when you pull the clutch level in, you should see very little resistance ie. a closed switch.
It looks like the site is mentioning that the situation can change when the switch gets warmed up (like 100 deg. F.) so the next test would be to do the same test as the first test, only heat the switch up with maybe a hair dryer and see if the switch operates the same. If all that is fine, the next thing to check is that battery voltage is going to one of the leads (confirm this first) and then check the other lead and see if it goes to ground. According to the site, when the clutch level is pulled in and the switch is made, the voltage coming down the one lead is shunted to ground which causes a voltage drop and the computer which is monitoring the voltage will see this drop in voltage and then send a corresponding signal to ??? Also when you check the ground lead, ensure that there's very little resistance between the end of the wire at the switch and the grounding point. The computer is looking for a certain voltage drop and if the ground point is dirty and has a high resistance, then the voltage drop my not be enough to tell the computer the proper information, so the computer will do nothing until is sees what it wants to see. Computer circuits are not happy when exposed to the outdoor elements and the same with the switchs and anything else hooked up to the computer. Computer can quite often work in millivoltages and milliamps. Add just a tiny bit of resistance from a dirty connection or high resistance from a loose connection and you've got trouble.
When all this switching is working properly, you should then be able to start the bike when the clutch is pulled in and that should confirm that aspect of that circuit.
So reading a bit more, I see that the switch is hydraullically operated and located down near the slave cylinder?.
The first question I have to ask is how is the clutch operating? I see that there are some concerns about faulty slave cylinders but it doesn't say just what the problem is with the slave. Is it leaking fluid? If so the only way fluid can leak out is if air is allowed in to made up the loss in fluid. If there's air in the system, then it's possible that there's not enough hydraullic pressure to operate the switch. Just throwing this out there for consideration. So like in the "other post" I mentioned that my Control Techs always told me that the problem is mechanical? In this case, it is possible that the hydraullic fluid pressure isn't enough to actuate the switch (something that the Ducati site doesn't talk about)
Let us know what you figure out
