Garage Door Opener Q&A

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Dear NH,

I have an automatic garage door opener that seems to have a mind of its own. We unplugged it about 6 months ago because it mysteriously kept coming open by itself, and I would have to disengage the opener to get the door closed because neither the remote nor the button on the wall would operate the door.

Last week, I plugged it in and it seemed to be working fine… the remote worked and the wall switch worked the few times I tried them. Then I went on an errand and when I came back, sure enough the door was open and I had to disengage the opener to close the door... Any clues as to what could be going on?

L in Texas


You either need an exorcist or a good garage door person... or both.

The occurrence of the door opening and then the remote not working could be caused by a short in either the wall switch or in the two wires leading to it. If these two wires were somehow to touch, the door would open but then would be disabled until the touching wires were separated. Check out the wires themselves, the screw terminal connections at the opener itself, and at the switch to be sure there are no bare wires touching. If the wire goes through a concealed location to which you have access (such as an attic over the garage), look there too. Mice have been known to chew the insulated covers off wires!

You can, of course, check the continuity of the wires using a multimeter. Disconnect the wires from the opener and the switch, be sure they are not touching, and touch the probes of the multimeter across either pair of wires. If there is a resistance reading, then there is indeed a concealed short.

If the wiring is OK, you might want to change the security codes on the opener and remote. Maybe a neighbor somehow is activating your door. I have heard that even some radio transmissions, such as from airplanes, can also activate garage door openers… or is that just another "urban myth"?

Otherwise, my next guess would be that one of the circuit boards within the opener is defective, and will need replacement.

Dear NH,

What is required to be done with garage door mechanical hand lock when a remote door opener is installed?


Dear JM,

You must disable the garage door lock mechanism so that it cannot be inadvertently engaged. Accidental locking may cause severe damage to the door or the opener if the opener is activated!

Since you (or the next owner) might want to lock the door, don't do anything permanent. A bolt through the latch bar so it cannot engage in the track is fine. You may have to drill a hole through the latch to accomplish this. You may also use a small padlock instead of a bolt.

Since local building codes are so finicky, I wouldn't doubt that some areas might even require a "permanent" disabling of the locking mechanism. If you are concerned, check with your local building inspector.

Dear NH,

Do you know the operating frequency of garage door openers?


Dear P,

I tried to search the FCC database myself.  I can tell you the proper frequency for a freighter sending a distress call in the Mediterranean Sea, but garage door openers... forget it!

However, a knight on a white horse has come to the rescue. After sending out a distress call, I received this response from Karl Seidel of Aleator Garage Door Transmitters (now defunct, unfortunately). Aleator was an online supplier of replacement garage door remote controls:

"The range of different types of frequencies depends on a variety of factors: geographic location, manufacturer preference, etc. We stock and sell radio sets with the following frequencies (in MHz): 288, 300, 310, 312, 318, 340, 390, 434, and more; we commonly get inquiries from Canada & other countries that use other frequencies."

 Dear NH,

I have an Automatic Doorman (Model 455) garage door opener (which was in our garage when we bought the house). Lately, it has not been working correctly. Sometimes when it raises the door up, it will not pull up quite100%. It almost gets to the end and then sits there humming until you push the door up an inch or so. This is aggravating but manageable. The main problem is that it does it on the other end too. That is, when it is putting the door down, it will get the door all of the way to the bottom and then sit there humming trying to force the door further. If you pull the plug, it shuts off. You can plug it back in immediately and it will be OK.  It is an intermittent failure. It does seem to operate correctly more often when the temperature is colder, but once it warms up, it fails almost every time.

I tried to look for the company on the web, but didn't find them, so I'm guessing they may be out of business. Do you know anything about this problem. Is there a bad limit switch in the unit, or is there something else wrong? I appreciate your help if you can provide me with any relief for this problem.


Dear BB,

Unplug the opener, open the unit up and look inside. I am not familiar with your specific opener model, but from your description, I wager that this opener uses drive belts instead of gears or chains. This would explain whyit continues to run rather than stopping or auto-reversing. The belts are slipping.

Remove the belt(s), take them to a hardware store and get replacements. Clean all the pulleys with lacquer thinner or alcohol to remove any grease or oils before replacing them.

The fact that you are having problems at the limits makes me wonder if you may have some restriction in the door itself. Troubleshoot the door for resistance, check pulleys, etc. There are some good tips in the garage door article at the web site.

Dear NH,

I've just purchased a replacement garage door remote from Sears. Can I program it to open both of my garage doors?

BM from Pensacola, FL


It depends whether or not the remote you purchased has that feature! Some remotes do allow you to open two doors, but the remote would have two buttons dedicated to garage door opener frequencies. Others have multiple buttons but they will only operate other features of Sears openers, such as turning on lights.

If you didn't get instructions or lost them, has instructions for many currently available openers, as well as compatible remotes for virtually every garage door opener. Their url is  .