I am just lucky that DH knows what he is doing??? Most of the time anyway!!! But I am also a "Turn off the entire house to change anything other than a lightbulb"!!! Its nice to have the on/off switch out there, especialy when working on the pumps or moving lighting arround.
All parts can be found at Lowes, Home Depot, etc. Print off the photo and take it with you and they should have all the parts. Make sure you tell them its for outdoors, these seal pretty good, the cords come out the bottom when the lid is closed. The light sensor is found by the outdoor lighting stuff.
The light sensor works really well. You can get 2 types, one that stays on when dark and one that runs for 4-5 hours and shuts off. I really dont use the lighting much, only when enjoying an evening outside. As it gets too warm here in TX and I dont want to cook the fish with the lighting on alot.