The light on my BuildMark opener won't come on. The door works well, and both the light button and the safety sensors trip the relay for the light. A check with the AC voltmeter shows 15 VAC when the relay trips and 0 VAC when it resets. I've tried twisting the bulb back and forth several times to see if oxidation is the problem, but that doesn't change anything.

I know the bulb is good (tested in other fixtures). Something is causing a low voltage at the bulb fixture. Suggestions?

2 Answers 2


There are two possibilities that I can think of that may be causing the problem with the light on your garage door opener.

  1. There may be an internal relay within the opener that turns on and off to control the light. The electrical contacts in the relay may have become burned and producing such a high resistance connection that even a tiny load drops the voltage way down. In this case it may be possible for someone reasonably handy with a soldering iron to remove and replace the relay.

  2. In the second case the light bulb socket on the opener may be controlled via an AC switch component called a triac. These switch on and off via the presence of a electrical signal from the opener control circuit board. Triac switches can fail and cause the symptom you see where just a fraction of the applied voltage makes it to the light bulb socket. Failure of these is most commonly caused by power line spikes from storms and lightning. They can also fail due to current surges caused when a light bulb burns out and the fractured filament swings around and momentarily shorts out the internal light bulb electrodes. Triac replacement is possible to do for someone experienced in working with printed circuit boards. The tricky part can be identifying the proper replacement component.


Here is a copy-paste from the manufacturer..

Why won't my garage door opener light turn on?

There are four causes for the lights on a garage door opener not to come on.

  • Light bulb
  • Contacts in the light socket
  • Light socket
  • Logic board

Light bulb

Verify that the light bulb has been replaced.

Contacts in the light socket

If the light bulb has been replaced and the light is still not coming on, follow the steps below to pry out the contacts inside the light socket.

  1. Unplug the opener. If, there is a back-up battery, disconnect it. WARNING: Failure to unplug the opener may result in electric shock.
  2. Take out the light bulb.
  3. With a small flathead screwdriver, pry the two contacts inside the socket out so that they will make better contact with the bulb.
  4. Put light bulb back in, if there is a second light, repeat above steps.
  5. If there is a back-up battery, reconnect.
  6. Plug the opener back in. Test the lights.

Light Socket or Logic Board

If the light is still not coming on, it could be the light socket or the logic board. To determine which one it is, follow the steps below.

  1. Unplug the garage door opener, then immediately plug the opener back into the electrical outlet. Listen for the light relay on the logic board to click.
  2. If you hear a click, replace the light socket
  3. If you do not hear a click, replace the logic board.

Note: This does not apply to garage door openers that use a work light that is separate from the garage door opener.

  • Thanks for the responses. I was hoping it would be something I could do without taking down the unit, but it sounds like it's the triac. The relay clicks on and off, as I described in the original post, but I guess the contacts could be burned. Either way, the problem is inside the box. :(
    – Bill N
    Nov 26, 2013 at 17:34

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