There might be a micro-switch on the linkage that is engaged. They are small and take a tine movement to engage and even less dirt and grime to make them stick. You might look closely at the linkage to see if that is something like that. It may be about 1/3 the size of a box of matches. If you find it, get a spray can of electrical cleaner with the little red stem. Blast it a few time from all directions. Then use a "gentle" air blasting to clean the solvent out. Make a couple applications and see if it clears up. If not, you might try to see if the switch is disengaging with a multi-meter by checking for conductance during the switch operation. BAIs there a way to disable the warning light and buzzer