For a couple of months or so, both of our garage door openers in the car have mostly worked in raising the garage, but mostly not worked in lowering it when we back out. I checked the beams and connections and everything seemed fine. I thought it was a remote problem given that it didn't always fail or always work one way or the other. Bought cheap new remotes. Same problem.
This morning, when I was unhappily awake at 5am, I decided to Google it. It turns out that if you put an LED replacement bulb in the lightbulb socket, it emits a radio frequency that can interfere with the wireless remote. And this would explain the mostly one-way problem: When you back out, you cross the beam and trigger the light if it wasn't already on from the door-side opener. So with the light on, it won't go back up. The times it worked was when I kept cursing the remote for long enough for the bulb to go out on its own! And it worked coming home because the light was off, except perhaps when I came home just after Sarah and the light was still on.
So it was off to the hardware store to buy some incandescent bulbs to test this theory. First thing I did was take the LED bulb out before leaving. Backed out, hit the remote. Boom, worked just fine. Theory seems confirmed! Got me some bulbs. Came home, went up just fine as mostly usual. I even waited in the car and closed it again. No problem.
After pulling in, I put an incandescent in there. Remote still works fine but the bulb now won't light up. Sigh. It's not the bulb as I checked two. Perhaps the LED damaged the socket or the circuit board. I even got out the big ladder and unplugged and replugged the unit. I think I heard the circuit board click on, but still no light.
We have needed a garage door tune-up anyway, so now for sure. Competition has driven the price down to $59 with a coupon. Seems worth it to tune it up and see what the bulb issue is. In any case, the remotes are working, which is the big thing, and I love solving problems like this.
The two employees at the hardware store liked this story too and perhaps may save a future customer from some headache knowing this.