Help: Under Hood A/C Actuator (for fresh air door)

[hooverfish]

Ordered a new Actuator and the center metal arm spins around, it is not in a fixed position.
Installed it, when it's actuated it jumps out of the arm on the firewall.
Sent it back, got another one from another supplier, same problem.
Original that came off the truck has fixed arm.

So, do I have to wire this thing together ?? Anyone else experience this problem ??