exhaust fans turning on garage door opener lights


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Old 04-26-16, 09:52 AM
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exhaust fans turning on garage door opener lights

So I am not sure what to make of this situation... Hoping all you experts will know!! Any time I turn on an exhaust fan in my house as soon as I flip the switch off it turns the lights on that are hooked up to the garage door. It does this with every exhaust fan in the house (laundry room, guest bath, and master bath). At first I thought it was something to do with the motion sensor on the garage door opener. Replaced that and still had the issue. Next, I thought it might be the logic board in the garage door.... fixed that and still had the problem. Finally, I tried unplugging the garage door, plugging it into an extension cord and plugging it in to a random AC outlet in the house, and what do you know.... the same problem!! Does anybody know what could be causing this issues? I know its not really a big deal because the garage door opens and functions correctly. It just drives me nuts that flipping the on/off switches on my exhaust fans cause the garage door lights to turn on.
 
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Old 04-26-16, 11:03 AM
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Brand and model? Does it have a wall station with a button to turn on the light? If so, is it wired or wireless? If wired, I would try disconnecting the wall station temporarily (at the opener end) and see if problem goes away. If wireless, take out the battery or disconnect AC adapter and repeat the test.
 
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Old 04-26-16, 03:05 PM
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The garage door is a craftsman 3/4HP model number 139.53990. Yes it has a wall station that you can turn on the light. It is wired with 2 wires that go from the garage door opener to the wall station. I turned the lights off on the garage door opener. Removed the wall station off the wall and disconnected the 2 wires. Flipped the switches for the exhaust fans and the light on the opener did not come on. So thats promising... If its just 2 stand alone wires that go from the garage door to the wall station what would cause the exhaust fans to trip the lights? How should I prevent that?
 
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Old 04-26-16, 07:52 PM
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Has it always done this or did it just start happening?

This is a guess.

This is what I think is happening: At least some craftsman openers use capacitors inside the wall station to be able to control three functions (door, light, lock) using only two wires. The door button just shorts the two wires. The lock button connects a small capacitor across the wires. The Light button connects a bigger capacitor across the wires. There is circuitry in the opener to distinguish between the three and do the right thing.

Sensing a capacitor at the end of a long pair of wires is a process that is susceptible to picking up electrical noise, and I suspect that's what's happening in your case. It's picking up the little bit of electrical noise caused by switching off one of your fans. How or why could be tough to figure out.

Get yourself a doorbell button and connect it to the two wires. It will only open and close the door. If the problem is gone with the doorbell in place, and you don't need the light and lock function on the wall station, you're done. If you do need the light and/or lock function, then you'll probably have to try replacing the wall unit.

You could also try replacing the wire with twisted pair wire or even shielded twisted pair; replacing the mini-zip cord type wire that is usually supplied with openers. But that's a long shot.

Good luck!
 
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Old 04-27-16, 03:20 AM
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I just bought this house a few months ago and have noticed the issue. I bought the identical wall unit and tried that as my very first fix. But unfortunately it didn't fix the problem. However, I used the same 2 cables that were with the old one. Maybe I'll try running the 2 new cables and see if that fixes the issue...
 
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Old 05-01-16, 09:16 PM
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Buy a two-conductor plus shield cable at an electronics store. Connect the two wires up in place of the old ones. Ground the shield to the metal case of the opener. Do not connect the shield at the button end.
 
 

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