Clutch Switch: Description and Operation

Vacuum valves (pedal valves)






These are identical. A spring-loaded piston actuates a micro switch and a vacuum valve. The valve is sell-adjusting as small plastic catches hook on to the piston, holding it in place.

When adjusting, the pedal is pressed down so the piston can be removed. The pedal is then released carefully so as not to push the piston back too tar.

In the normal position, with the pedal up, the spring is compressed, the switch contacts are closed and the vacuum valve is closed.

When the pedal is pressed for braking or declutching, the spring forces the piston back.

This opens the switch contacts, so that the ground circuit of the control module terminal 9T opens and de-energises the relay. At the same time the vacuum valve opens, admitting ambient air and disengaging the cruise control.