2008 Impala Wiring

I have a 2008 Impala with an expired onstar system. I want to convert the onstar button to open/close my garage door. To wire in the remote, I need to locate the onstar computer. I don’t want to tear down the headliner to trace out the wires. Does anybody know where the onstar computer is located on these cars so that I can get to the wiring terminals?

How can you force the On-Star transmitter to transmitt a garage door signal if it is not activated? Are you sure all the OnStar computer needs is +12v and a ground and it goes? You would be better off with the GM Home Link garage door opener or a aftermarket door opener.

While I agree that the GM-branded garage door opener would be the better solution, I think the poster just wants to know where the OnStar button’s wiring terminates so that they can connect it to a third-party garage door opener.

I’m going to take a wild shot in the dark and say that the button is probably sitting right on a circuit board and would be pretty hard to interface with. I bet if you could weasel your way in to a Chevy dealer and talk to a tech, they could give you an idea.