Does anyone know how to troubleshoot a malfunctioning garage door opener? Mine keeps going up and down until I remove the AC power plug. I checked each individual limit switch (4 of them) with a continuity checker and they're all OK. Could it be an alignment or timing problem with the limit switches? I recently cleaned the relay contacts with contact cleaner. Any advice will be appreciated.

 

If it hits the closed position before the bottom or sense closed switch, it thinks it has hit an obstruction and reverses.
Max.

 

Try reading the manual, for the setup procedure. As Max says, it's probably trying to go a bit too far and reversing when it thinks it is hitting an obstruction.

 

I don't have the manual. The door opener is about 30 years old and it was there before I bought the house. Could this be caused by the house settling or sinking after so many years? Maybe the door is hitting the ground too soon?

 

Maybe the door is hitting the ground too soon?

Its hitting the ground at the right time , just that it may not be seeing the bottom limit switch,
Unless it is not going to the bottom, then in that case it is binding or the friction/obstruction or stop detection is not set right,
The adjustment is usually in the head unit itself.
Max.

 

Who knows. I was replacing the bulb in mine just last night and discovered it wasn't burnt out - it had just loosened in the socket. Vibration over the years may have altered your settings.

Don't dismiss the internet. A search on your model number might surprise you.

 

Try reading the manual, for the setup procedure. As Max says, it's probably trying to go a bit too far and reversing when it thinks it is hitting an obstruction.

It could be settling, it could be corrosion or any other stiff bearing in a roller.

Before you get into major troubleshooting, you could ask yourself if it is time for a new opener.

If not, start by disengaging the opener and making sure the door rolls up and down freely. The springs should be balanced so it doesn't take too much force to lift all the way or close all the way.

Then, connect the opener and follow the basic installation/setup instructions from any door opener - they all work the same way (first set the limits, then set the tension required to initiate reverse when closing). It should reverse even at 3" from full close (2x4 board on edge to simulate obstruction).

Finally, test that the IR sensors work in case of an obstruction. They should be located about 6 inches from the ground.


Honestly, if you have kids (grand kids) or pets, I would spring for an updated opener that I had confidence in - knowing it will reverse every time it hits an obstruction. A 30 year old door opener needs some stress testing to make sure all sensors work.

 

For what it's worth, I occasionally test my door by grabbing it when it's closing, to see if it reverses. It does, but I'm not sure either of my cats would actually survive the force required to reverse it. Most children would be fine.