Make sure the battery connectors to the reciever is in it's slot. By the way, go to hobby shop tomorrow and buy 5 cell hump or flat pack of rechargeable batteries with futuba style connectors and install that with a new switch that has charge plug 3rd wire. You will get better response with servos and make it easier on you to charge and not have to rely on high cost batteries. I also used a Y-harness connector to plug new battery wire and throttle wire together and plugged in the throttle input on receiver. Gives higher voltage to servos and makes them turn faster. This tip is all over the forum so info is nothing new.
Rockman