Added a doorbell push button to newly installed Chamberlain garage door opener...linked push button wires to same contacts as the incoming control pad inputs (red and white). Doesn't work. Is this wired incorrect?

3 Answers 3


A regular push button either normally closed or open will not work on most modern garage door openers, because the control pad doesn't just short or open the wires. They use resistors or some other mechanism to vary the voltage going back to the motor controller.

You must purchase a Chamberlain compatible push button.

  • 2
    Thanks! Appreciate it. I'll just buy another remote and mount it on wall.
    – bob brock
    Jan 3, 2016 at 16:21

RE: LW3500 unit.

I like the wiring across the switch solution (above) in many cases, but I did not want to run wire over to the main switch. So, having another unit that I have not yet installed I did a little research.

Across the two input connectors are:

1 A 1500 ohm resistor in series with a green LED. Power light.

2 The primary switch with nothing else. In other words a dead short when pressed.

3 The Lock switch is wired in series with a 22uf cap. Long pulse when pressed.

4 The Light switch is wired in series with a 1uf cap. Short pulse when pressed.

CAUTION: these Caps are polarity sensitive, but if the LED lights, you wired it correctly.

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  • @Daniel Griscom — LW3500 is a Chamberlain garage door opener model number. Ken Srigley's answer is relevant to the question.
    – Andrew P.
    Nov 21, 2019 at 4:00

You can take the wall unit apart, find the tiny switch that is activated by the large outer button, figure which two of the leads(spider legs) short together, solder two wires there, and that's your alternative cheap fix. I did have to buy a pencil style soldering iron.

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