ok, sorry guys .. it was on this other site. tried to copy the diagram . but won't copy over... this won't take more than 3 minutes to put together. will take longer to splice it in, than to put it together.
http://www.the12volt.com/relays/page5.asp#ctm
but this one web page will allow you to use just about ANY switch you want to use...or have available... even a blinking turn signal!
The capacitor allows the coil of the relay to be energized until the capacitor stores a charge, thus de-energizing the coil. This one will give you about a 1/2 second output. The resistor bleeds off the charge of the capacitor when positive voltage is removed from the other side of the coil. You can increase the output
time by simply changing the value of the capacitor to higher capacitance.
basically for about 4 bucks, when you toggle the high beams, it will activate the garage door opener for a half second and then it releases or stops, UNTIL the next time the high beam gets toggled.