I have a Chamberlain 045ACT garage door opener. It has a wired push button for opening and closing the door. I want to add a second button, so I can open and close it from two different places. How do I do this? Have you tested to verify it works?
The pushbutton is an N.O. (normally open) switch. When you press it, the circuit is closed and the opener starts its cycle. It's easy to add a 2nd pushbutton by wiring it in PARALLEL to the first one. That way EITHER one, acting alone can control the door.
For a diagram of this see the 'Switches in Parallel' diagram at: