motor shut down after changing water pump

20002 chevy express will not crank over but iI have all the lights on the dash when I turn the key on ;Blower motor don:t come on nor fuel pump. I put a water pump on it,s a4.3 vorteck the motor just shut down. I have all of my dash lights when i turn the key on but my heater blower don.t come on i don.t have power to my fule pump I ingage the key to start nothing 0 my head lights go off untill i let go of the key