For 1990-2009 cars

The garage door opener is located inside the rear view mirror. B+ and ground is supplied to the garage door opener through the inside rear view mirror connector. Terminal 11 supplies B+ when the ignition switch is in the ON position and terminal 8 supplies ground at all times.

The garage door opener switch assembly contains three switches. The garage door opener has the capability of learning up to three different universal transmitter signals. Each signal is associated with a switch. The garage door opener transmitter accurately activates the applicable garage door opener receiver after learning a signal. The garage door opener transmitter transmits a default signal that permanently stores in its memory if a switch that has never been programmed is pressed. The garage door opener transmitter transmits the default signal from the lowest numbered switch that was pressed if more than one switch is pressed.