ST. CHARLES COUNTY • The garage door opener mystery on Westhampton View Court is solved.

The landscape lights transformer did it.

The five homeowners who live on the cul-de-sac near St. Peters had been trying to figure out why their garage door remotes quit working shortly after Christmas.

On Tuesday, two residents decided to do a systematic check of everything electric in their homes.

Hannu Heinonen went to the circuit box in his basement, and powered down everything but the garage door. Then he let Gil Ballman know via cellphone. Ballman clicked the garage door remote button, and the door opened.

"All of a sudden I heard a garage door open, and I thought 'This is wild.'" Ballman said. "I said, 'Hey, guess what? It's you, Hannu.'"

By turning on the circuits one by one, the men determined that the culprit was a 24-volt transformer box in the basement for lights in Heinonen's yard.

He's had the transformer for four years; it's unclear why it just recently started interfering with the whole neighborhood's garage door openers.

"It's not exactly rocket science; it's the most basic technology in electrical engineering," Heinonen said. "But I'm the bad boy, I guess."

A garage door repair company recommended that homeowners switch to another frequency, a fix that could cost as much as $400, but homeowners balked at the expense and looked for other solutions.

They investigated a range of potential causes — everything from new Christmas gadgets to lightning strikes to high-efficiency light bulbs — but couldn't find the problem.

Chamberlain, the manufacturer of the neighbors' garage door openers, had planned to fly in one of its district managers to conduct a test with residents this week.

After hearing that the problem was solved, a representative of the company offered each of the homeowners a complimentary accessory to go with their garage door opener.

Homeowner Kathy Hoechstenbach, said she was just glad to have her garage door opener back after six weeks of having to park her car in the driveway, go inside her home and activate the door from a hard-wired button in the garage.

"This is going to be like a real luxury to me now," she said.

And the fix seems to have come just in time: Snow showers were in the overnight forecast.