I just finished fixing my own interlock switch. All it needed was to be removed for a cleaning and put right back. It was the grease in the switch that got dirty over the years, and, some WD40 took care of it. To remove the switch, unplug it, then pull down on the release tab at the base of the clutch master and pull the switch back a 'lil. Now turn the switch sideways to reveal the top side. The top is actually the retainer and is released by depressing the 2 tabs at the rear and sliding the retainer backwards until free from the rest of the switch . Now you can pull the switch off the clutch rod. Clean it with whatever cleaner you choose (WD40,brake cleaner or simular, no carb cleaner). You can cycle the switch with a small screwdriver to observe the action and see how the switch works. When you place the switch back over the rod, start by snapping the rear section on the rod as close to the c/master as you can.To snap the front section over the rod, you must depress the mechanism inside the switch (pocket screwdriver)while trying to snap the switch over the rod. You will have to remove the screwdriver before the final snap. Now without disturbing the switch, replace the top retainer, and rotate the switch back to normal and push it against the c/master making sure the release tab engages the post on the switch. Plug the wires and enjoy !
Phil