You need a small, blunt tip probe to push down on the metal tab in the top opening. This will release the wire clamp in the bottom opening to add or remove the wire.
Send me a PM. I also have access to external H-relay circuits that act as the actuator
power control, and converts the APU 100 internal relays to only
low power control devices. This will prolong the lifetime and
reliability of the APU100 by offloading high
current control requurements.