What exposure mode are you using? If the exposure is not correct, the WB can not be measured. Try puting the camera in Program mode. Are you using a gray card or a White Balance tool like an ExpoDisc? If you are using a gray card, is the gray card completely filling the frame? If you are using an ExpoDisc or other WB tool are you aiming the lens towards the light source? Good Luck and Enjoy your Nikons!