Craftsman Garage Door Opener: Rogue Remote

Just before midnight, the garage door opened, but, being early-to-bed folks, it wasn’t either of us. I pulled my fingernails out of the ceiling, padded out to the garage, verified there was nobody (not even a critter more substantial than a spider) inside, closed the door with the hardwired control button on the wall, and went back to bed. An hour later, the door opened again, then tried to take a bite out of me when I walked under it.

I pulled the opener’s plug, yanked its emergency release latch, lowered the door, and returned to bed; it was not a restful night.

The key to the diagnosis came from the little yellow LED on the back of the opener, just above the purple LEARN button:

Craftsman Garage Opener - indicator LED
Craftsman Garage Opener – indicator LED

In addition to indicating various programming states, it also lights when the opener’s radio receives a transmission from one of the remote controls. The LED was flickering continuously, showing that something was hosing the receiver with RF.

We have three remotes: one in the car, one on my bike, and one in the back room overlooking the garage. None of them worked reliably, suggesting the RF interference was clobbering their transmissions.

Disabling the remotes by removing their batteries (which were all good) also stopped the interference. Reinstalling the batteries one-by-one identified the rogue opener:

Craftsman Garage Opener - remote innards
Craftsman Garage Opener – remote innards

The slip of paper let me isolate the battery terminal and stick a milliammeter in the circuit, which showed the remote was drawing about 1.5 mA continuously. I thought one of the pushbutton switches had gone flaky, but swapping an unused one for the main door switch had no effect.

I lost track of which remote it was, but it lived in the car or the back room for all its life, so it hasn’t suffered extreme environmental stress. I have no idea why it would fail late one night, although I admit to not monitoring the LED on a regular basis. For whatever it’s worth, in the weeks leading up to the failure, activating the opener sometimes required two pokes at the remote, but nothing bad enough to prompt any further investigation.

A new cheap knockoff remote arrived in few days and it’s all good.

Protip: different openers, even from the same company, use different RF frequencies. For Craftsman openers, the color of the LEARN button is the key to the frequency; purple = 139.53753 MHz.

4 thoughts on “Craftsman Garage Door Opener: Rogue Remote

  1. Sounds familiar, but for me, it was a 64G thumb drive in the Forester. (I use 24G worth of it for the CD->MP3 conversions.)

    I’m pretty sure it was heat; the drive sits in the car and it got pretty toasty on market days, and the trips over the Cascades coincided with some hot weather. All I know is that the drive went radio silent. Could not get anything from the computer.

    I’m also going with an extension cable for the new one to reduce pressure on the connector. That seems to work well on the Honda.

    1. Subaru must have upped their infotainment game, because back in 2015 they had a 16 GB limit for “USB Storage Devices”. Finding out if a 16 GB partition on a 64 GB device will work seems like a Good Idea, because they don’t make ’em that small any more!

      1. According to the Subie 2 manual (2016) there’s a description of the limits. Found it on the dead-tree manual in the car, but can’t find it in the PDF files. Arggh.

        IIRC, it’s number of folders (500ish) and a certain number of files per folder (perhaps 255). 64GB thumbs with Fat 32 formatting work fine. OTOH, it’s very fussy as to how the data is loaded. If file 2 gets loaded before file 1, the play sequence is 2, then 1. Oops.

        FWIW, 16Gb SD drives with USB adapters should work. Haven’t tried myself, but those are fairly available at the ‘zon.

        I ended up doing a script that copies each filename in order for each named folder. Musicals and sequential work can be quite, er, interesting without that trick.

        1. Sounds like the ancient MP3 player Mary used to use for audiobooks, where cp scrambled the order and rsync worked fine, at least after I figured out how to name / number the tracks properly.

          Good clean fun, indeed!

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