Turn the alarm sensor so the back of its plastic case is facing you. Sand the center of the back lightly with a piece of 120-grit sandpaper, to create texture that will assist in the adhesive bonding process.
Wipe the sanded area with a dishcloth to remove any loose grit.
Squirt a quarter-sized dollop of a clear silicone-type adhesive to the area of the sensor you sanded.
Press the back of the alarm sensor to the vinyl window at the desired location. Hold the alarm sensor in place for three minutes.
Do not disturb the alarm sensor for at least 24 hours while the adhesive bonds with the vinyl window’s surface.