Yes, you must first be receiving a satellite signal for a check switch to work! If the receiver has not been connected to satellite in more than 30 days then Dish (or DirecTV) receivers will shut themselves down and you will not be able to receive programming until you call Dish (can be done online with DirecTV) and have them send a reactivation signal.
Channel 100 or 101 will give you a picture even when no programming is available as it's just Dish or DirecTV promos.
Use the built in signal meter in the receiver to ensure you have a good signal from the right satellite but as mentioned above an app on your phone will really help you locate the satellites. I like Augmented Reality Dish Pointer.