Hi Jack,

There is no need to key frame every second unless you want to. For example, if you want the lights to dim over 5 seconds, simply place a key frame at the point in time you want the fade to start and then set the next key frame 5 seconds later with the light as dim as you want it to go. 

As for the light switch problem, it sounds like you have the Tweener set to Discrete. Try Bezier or Linear instead.

Mark