There are four traps around the map, you need to restore and kill zombies with them.
The Electric panel is found on a bench near the bus. After turning on the Power, bring the panel to the broken panel at the fence and it should be working. The trap electrifies your surroundings and its need to power up the Alien Fuses.
You need a panel that can be found to the left of the garage at the gas station. Grab it and go to the freezer room at the supermarket. Put the panel at the wall and turn it on, it will freeze the zombies when they try to enter the place. It is needed to get the zombie torso for the Main Easter Egg (See Soul-Less).
You need to refuel the engine with some gasoline. It can be found on a truck near the stairs leading to Elvira's place. Get the fuel and put it on the engine, it will turn on and electrifies the pool, killing zombies that jumps in.
The fire trap need some valves that can be found on a table near the Volk. Put it on the tank behind the trailer and it will spill some liquid that will violently spread the fire like a flamethrower.