D^2 I have several 1968 Imperials with the vacuum trunk release, it will work with the engine and key off, but only about two or three times, before you must start the engine to build up more vacuum. If you know you are going to open the trunk, do it before you shut off the engine, then you have a reserve of vacuum in case you need to open the trunk several times without starting the engine again. Bill/Imp 68's