Turn the prop off then disconnect the form of power (remove the batteries or unplug the product). Check the instructions to make sure all pieces and wires are properly connected. Reconnect the prop to its power source and turn it back on to see if it is now functioning properly.
You may also want to check and make sure the sensor is clear of obstructions. Sometime the fabric of the prop may get in the way. Also, props relying on a motion sensor need to be placed in a well lit area. If the prop is set in shadows with no definite way to sense a break in the light, it may not function as anticipated.
For additional assistance please contact our Dr. Zombie tech support via the live chat link at the top of the page, email us at AmazonGuestServices@spirithalloween.comor call us at (856)-586-0155 option 5.