I have a Stanley ST400 garage door opener. I replaced the safety Sensors and still can't get a green light. I have hooked the sensors directly to the door opener and still no green light!

Google craftsman or customer service sears/utube

This sounds like a problem with the safety sensors; either due to a blocked path between the safety sensors, condensation, mis-alignment, dirty eyes, loose wires at the sensors or at the motor head, or just bad safety sensors. When the infra-red safety sensors are malfunctioning, usually one of the sensor lights will be blinking or a blinking red light will show rather than green or amber. The sensor lights need to be solid and not dim or flickering.

When the sensors are at fault, the remotes cannot close the garage door; they can only open it. You may find that the door will only move an inch or so in the close direction. When this happens, your garage door will only close by holding down on the wall button until the door fully closes. This method is the only way to override the safety sensors and close the door. This is also a direct clue that the safety sensors are the problem.

Also, try unplugging the garage door opener and re-plugging the unit back into the outlet. This can act as a reset and may reset the sensors. If none of this works then you may have to replace the sensors or possibly the logic board inside the motor unit.

Hi Vickie,

The safety beam portion of the garage door opener is set up to stop the door from closing if something (car, person, etc,.) is in the doorway.

When the door is open - if you press the hard wired push button (not the wireless remote) the door will either close until shut completely, or begin to close and reverse direction as soon as you let go of the button. When this happens, it *usually* means that a sensor is blocked - and reversing the door motor. If you try yhtis with the remote the door may not move at all or just bump down and stop.

You should re-align the sensors as described in the link below. Good luck!


How to Replace the Safety Sensor for Garage Door Opener Repair Guide Help...

How to Adjust Photo Eye on Garage Door

Check to see if sensors (eye) on sides of door are lined up, they need to be looking directly at each other. If that doesn't work change sensors, simple, install, hook up 2 wires per sensor, wire with line to same wire, blank wire to same blank wire and align so sensors see each other.

If you need further help, reach me via phone at https://www.6ya.com/expert/frankie_091f536560a54e12

The sensors are seeing something directly in line with the beam between the 2 sensors, or your sensors are not aligned so they point directly at each other.

try here

http://homeappliance.manualsonline.com/manuals/mfg/sears/sears_garage_door_opener_product_list.html

closest thing i could find

I am presuming the following: is it that the door will not operate unless you hold down the button to "close the door"? And the button you are pressing is the hardwired wall button or control inside the garage correct? And if you try to close the garage door with the remote the overhead lights flash off and on or the motor make a clicking sound (about 5 clicks?)
The problem is either an obstruction of the safety sensors at the bottom of the door or, one or both sensor eyes are out of alignment. If you look closely at both safety sensor eyes on the part that faces into the garage, you should see a glowing LED. One side will be an Amber color and the other Green. If one is lit (amber) but the other is not (green), that is an indication that the beam is not being received by the receiving eye (amber).
If there is no obvious obstruction (check for spider webs, dust, try cleaning the clear lenses facing each other, etc,) Try re-aligning the sensors. When they are properly aligned the Green LED will be lit. Now, check the motor for operation.
If you have difficulty getting the transmitter eye (green LED) to light, try closing the door at the wall button, then, pull the red emergency release handle to disengage the door.
Now, try operating the motor unit with the door disconnected while using the hand held transmitter. If the motor unit operates to the close position while the door is closed but not when opened, then that sounds like there is sufficient light entering the garage to "Wash" the transmitter beam out so the receiving eye does not get it.
Contact Chamberlain/Liftmaster for Sensor eye blinder shields that can be easily installed by you. (they just snap on) If neither LED is lit, make sure that the wire to the sensor(s) has not been cut off at the sensor itself. If that checks out, check the connection at the logic board. Make sure that both wires are securely connected.
If after checking all of that, and you do not have either of the LEDs on, then disconnect the safety sensor wires from the motor unit's logic board. Then take a 2" piece of bell wire and jump it across the two terminals for the safety sensors. If the unit operates normally when using the hand held transmitter, then the problem is likely: a) Bad safety sensors b) Broken wire to one or both sensors
To check if the safety sensors are good:
Remove both sensors from their mounting brackets. measure about 8" to 12" of wire from the back of the sensors and cut. You should have about 8 - 12 inches of wire on each. Now, separate and strip the insulation from each and then match the white striped wires and twist them together, and do the same with the solid non-striped wires. Take the sensors up to the motor head and connect the spliced wires to their respective positions on the logic board. Now, Point the two sensors directly at each other (its okay if the clear lens part are touching each other) Check if both LEDS are now lit. 1) If YES; then the sensors are good, the wire to them is broken somewhere; [FIX] replace the wires for both sides. 2) If NO: then the safety sensors need to be replaced. [FIX] Replace the sensors, contact Chamberlain / Liftmaster for replacement parts. You will need your garage door opener's model # which can be found under the light bulb or light fixture on the opposite side of the logic board. Having the model # speeds up the parts search for you.
I hope this helps you out. [I have been factory trained on residential and commercial garage door openers by Chamberlain / Liftmaster and have been providing installation and tech support on them for over five years. Prior to that I used to install and repair these units, and I've done that for nearly seven years.]

You may look at the safety sensors. Try holding the wall button down. If the door operates with the button held down then it is the sensors. Try to align them to look at each other. If not you are probably looking at either replacing the sensors or the logic board. Thanks BB

Your safety eyes are out of ajustment. Make sure that the eyes are pointing directly at each other. A light will come on on each eye when they are properly aligned. The only other thing that could be wrong is that one of the safety eyes could be bad, and the only thing you can do is replace the eyes. 99% of the time the problem is an alignment issue. By holding down the wall button, you are overriding the safety eyes.

Pull the contact wires off the back of the eyes. If this is found helpful, please post as such. Post as fixya if it gets the desired effect. TY