Why do the lights on my garage door opener flash and my door will not close?

The garage door opener is equipped with two safety features that may prevent the door from closing and cause the lights to flash.


The Lock Button on the Wall Control

The lock button on the wall control may be activated. Press the button to turn this feature off. The light bulb will blink two times. This feature is designed to prompt you that the lock button is activated. When the lock button is ON the garage door opener will work from the wall control but the remote controls are locked out.


The Safety Reversing Sensors

The most common reason for the lights to flash on the garage door opener and the door not closing is that the safety reversing sensors are misaligned or obstructed; this is a safety feature of the garage door opener.

When properly connected and aligned, the sensor will detect an obstacle in the path of its electronic beam. If an obstruction breaks the light beam while the door is closing, the door will stop and reverse to full open position, and the opener lights will flash 10 times.

Your garage door opener has a Self-Diagnostic feature. The LED next to the learn button will flash a number of times, and then pause signifying the potential issue.

One (1) flash indicates the sensor wire is shorted. See How do I test or troubleshoot the safety sensor wires?

Two (2) flashes indicate an open, broken, disconnected sensor wire, or the safety sensors are NOT installed. Consult your manual for sensor installation instructions or see How do I test or troubleshoot the safety sensor wires?

Four (4) flashes indicate the sensors are slightly misaligned. See How do I align my safety reversing sensors?

NOTE: The garage door can be closed by pressing and holding the Door Control push bar until down travel is completed.

How do I program my remote control?

Your remote control can be programmed to activate many devices, including gate operators, garage door openers, and commercial door openers.


Basic Programming Steps

  1. Locate the Learn button.
    • Garage door opener: Located on the back or side of the motor unit (you may have to remove the light lens). The Learn button may be green, orange, red, purple, or yellow with a small LED next to it.
    • Gate operator or commercial door opener: Located on the control or logic board, with a small LED next to it.
    • MyQ Control Panel: Lift the push bar and locate the learn button.
  2. On your Garage door opener, Commercial door opener or Gate operator:
    • Press and release your Learn button.
    • If you have a LiftMaster 8500 or 8500C, skip to step 3.
  3. On your MyQ Control Panel press your Learn button twice.
  4. Within 30 seconds, press and hold the desired button on the remote control.
  5. Press the remote control again when the opener lights blink. The operator or opener should activate. If not, repeat the steps.

 

How do I adjust the manual travel and force limits?

Limit adjustment settings regulate the points at which the door will stop when moving up or down. The door will stop in the up direction if anything interferes with the door travel (including binding or unbalanced doors).

To operate the opener, press the Door Control push bar. Run the opener through a complete travel cycle.

  • Does the door open or close completely?
  • Does the door stay closed and not reverse unintentionally when fully closed?

If your door passes both of these tests, no limit adjustment is necessary unless the reversing test fails.

Adjustment procedures are outlined below. Run the opener through a complete travel cycle after each adjustment.

Repeated operation of the opener during adjustment procedures may cause the motor to overheat and shut off. Simply wait 15 minutes and try again.

 


 

WARNING

Without a properly installed safety reversal system, persons (particularly small children) could be SERIOUSLY INJURED or KILLED by a closing garage door.

  • Too much force on the garage door will interfere with proper operation of the safety reversal system.
  • NEVER use force adjustments to compensate for a binding or sticking garage door.
  • After ANY adjustments are made, the safety reversal system MUST be tested. Door MUST reverse on contact with 1-1/2″ (3.8 cm) high object (or 2×4 laid flat) on floor.

Adjust Travel Limits

If the door does not open completely, but opens at least five feet:

  • Increase the Up travel. Turn the UP adjustment screw clockwise. One turn equals 2″ of travel.

NOTE: To prevent the trolley from hitting the cover protection bolt, keep a minimum distance of 2-4″ between the trolley and the bolt.


If the door does not close fully and stops short:

  1. Increase Down travel. Turn the DOWN limit adjustment screw counterclockwise. One turn equals 2″ of travel.
  2. If the door still won’t close completely and the trolley bumps into the pulley bracket, try lengthening the door arm.
  3. If you have adjusted the door arm to the maximum length and the door still will not close completely, lower the header bracket.

If the door reverses in fully closed position:

  • Decrease Down travel. Turn the DOWN limit adjustment screw clockwise. One turn equals 2″ of travel.

If the door reverses when closing and there is no visible interference to the travel cycle:

  1. If the opener lights are flashing, the Safety Reversing Sensors are either not installed, misaligned, or obstructed.
  2. Test the door for binding.
    1. Pull the manual release handle.
    2. Manually open and close the door. If the door is binding, call for garage door service. If the door is not binding or unbalanced, adjust the DOWN force.

Adjust Force Controls

Test the DOWN (close) force by following these steps:

  1. Grasp the door bottom when the door is about halfway through DOWN (close) travel. The door should reverse. Reversal halfway through down travel does not guarantee reversal on a 1-1/2 inch obstruction.
  2. If the door is hard to hold or doesn’t reverse, decrease the DOWN (close) force by turning the control counterclockwise.
  3. Make small adjustments until the door reverses normally. After each adjustment, run the opener through a complete cycle.

Test the UP (open) force by following these steps:

  1. Grasp the door bottom when the door is about halfway through UP (open) travel. The door should stop.
  2. If the door is hard to hold or doesn’t stop, decrease the UP (open) force by turning the control counterclockwise.
  3. Make small adjustments until the door stops easily and opens fully. After each adjustment, run the opener through a complete cycle.

If the door doesn’t open at least 5 feet:

  1. Increase UP (open) force by turning the control clockwise.
  2. Make small adjustments until the door opens completely.
  3. Re-adjust the UP limit if necessary. After each adjustment, run the opener through a complete travel cycle.

If the door reverses during the DOWN (close) cycle and the opener lights aren’t flashing:

  1. Increase the DOWN (close) force by turning the control clockwise.
  2. Make small adjustments until the door completes a close cycle. After each adjustment, run the opener through a complete travel cycle.NOTE: Do not increase the force beyond the minimum amount required to close the door.

After ANY adjustments are made, the Safety Reversal Test MUST be done. The door MUST reverse on contact with 1-1/2″ (3.8 cm) high object (or 2×4 laid flat) on floor after any travel and force adjustment.

 

How do I erase the remote control from the garage door opener’s memory?

There are a few instances that the memory of your opener would need to be erased.

  • An unwanted remote is activating your door
  • One remote button is activating multiple doors
  • Remote is lost or stolen

NOTE: Erasing the memory will remove ALL remote controls and keyless entry codes from the garage door opener.

 


To erase the memory perform the following steps:

  1. Locate the “Smart/Learn” Button on the back or side of the motor unit; generally this is on the same side as the antenna wire. You may need to remove a light lens cover or open a control panel to gain access. The “Smart/Learn” Button may be Green, Orange, Red, Purple or Yellow, and will have a small LED next to it.
  2. Press and hold the “Learn” button on the motor unit until the learn indicator light goes out (approximately 6 seconds). All previous codes are now erased.

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