I have an automatic garage door opener that continues to reverse itself when attempting to close the door. It'll go down a bit and then start to bring the door back up. I had to pull the release latch to get the door down. I had been using the door closer and for a couple of days had to hold the closer down as the door would try to reverse and go up. There is nothing between the sensors and the motor sounds great.

Check to be sure that the door sensors are properly aligned. They usually have an indicator light (usually green) that indicates when the receiver "sees" the transmitter.

What type of door is it - roller or tilt? Some types of doors have a current sensor in the motor circuit that detects an overload (usually from an obstruction) and causes the motor to switch to 'up' movement.

Check for dirt, corrosion, bent parts, or anything else that might provide abnormal resistance to the door or motor's movement.

The other possibility is a limit switch that's broken or badly out of adjustment.

When you tell us what type of door it is, we might be able to offer more specific advice. (A brand and model number would be even more useful.)

Daniel