mlseim–The problem is 2-fold. First, the pushbutton for the garage door is a significant distance accross/around the garage and running the wire would be unsightly.
The bigger problem is that I have one of the new/fancy garage door openers that sends a data signal to the door rather than just shorting the two control pins. The wired button actually has a control for the light and the door, so just shorting the pins on the opener doesn’t control the door. I’ve looked at the wiring diagram for the opener and there is no clear/easily accessable way to hook up a simple pushbutton opener.
My Imp is actually mounted on the opener, and I’d have preferred to just wire it to the opener with a relay…but it just doesn’t work that way…damn modern technology 
i use the imp to push a button on a spare remote, maybe that is a solution for you too…
@Chrischi–That’s exactly what I’m doing…but I’m also using the Imp to provide power to the spare remote (instead of batteries). My problem may be in how I’m “pushing” the button and my next troubleshooting step is to replace the direct connection from my Imp to the control with a relay to simulate the button. I just have to wait for the 3V relay to arrive in the mail.
@willis72 ok! my remote uses one of this fancy 9V Batterys and i use this circuit
Hugo suggested Circuit (01/2013) and the 9V Battery power to switch/push the button. Works for more than 1,5 years now…
Finally got it working. The problem was that there was a significant voltage drop when I tried to pull the pin high…enough of a drop to cause the Imp to drop offline. I still don’t know why it would work sometimes (usually right after a restart) and then fail later.
Thanks everyone for the help.
