Flood lights take a very long time to come on
I have installed your motion sensor light model SH-5412. The test went as described in the instructions. Night time is a different story. You say the lights should come on to full bright in two (2) seconds. I estimate it is at least 10 or more. It takes so long that I am at the garage door before they are fully bright.
Electrical Supplies - Heath Zenith
Answers & Comments
Insure you are using a standard flood light on motion sensor lights and not a florescent energy efficient flood light as they take longer to reach full brightness as the bulb filiment warms up. They are better suited for constant lighting rather than intermittent purposes such as sensor lights.
Good Luck